Maryland Counties. List Alphabetically (and by Population)
How many counties are there in Maryland? As of 2024, there are a total of 23 counties in the state of Maryland. Among them, Saint Mary’s County is the oldest one (established in 1637) while Garrett County is the youngest (established in 1872). With population of 1,004,709, Montgomery County is the most populated. The biggest county by land area is Worcester County (1,800 km²) and the smallest is Baltimore City (238 km²).
Largest Counties in Maryland
1. Montgomery County
County Seat: Rockville
- Area: 507 square miles
- Population: Approximately 1,062,061
- Area Codes: 240, 301
- Latitude and Longitude: 39.1362° N, 77.2014° W
Location and History
Montgomery County, located in the central part of Maryland, borders Washington, D.C., to the southwest and stretches northward towards Frederick County. Established in 1776, the county was named after Richard Montgomery, a Revolutionary War general. The region historically served as an agricultural center, with tobacco as the main crop. Over the years, the county has transformed into a suburban area with a blend of residential, commercial, and high-tech industries. The development of the Capital Beltway in the 1960s catalyzed its suburban growth, making it one of the most affluent counties in the United States.
Major Highways and Landmarks
Montgomery County is crisscrossed by major highways, including Interstate 270, the Capital Beltway (I-495), and U.S. Route 29. These highways connect the county to Washington, D.C., and other parts of Maryland, fostering significant commuter traffic. Notable landmarks include the National Institutes of Health (NIH) in Bethesda, the headquarters of the Food and Drug Administration (FDA) in White Oak, and the historic Great Falls Park along the Potomac River. The county is also home to the vibrant city of Rockville, with its historic downtown area, and the bustling Bethesda Row, known for its dining, shopping, and entertainment options.
2. Prince George’s County
County Seat: Upper Marlboro
- Area: 498 square miles
- Population: Approximately 967,201
- Area Codes: 240, 301
- Latitude and Longitude: 38.7849° N, 76.8721° W
Location and History
Prince George’s County is situated in the central part of Maryland, to the east of Washington, D.C. The county was founded in 1696 and named after Prince George of Denmark, the husband of Queen Anne of Great Britain. Historically, the county was an agrarian society dominated by tobacco plantations, supported by enslaved labor. With the expansion of the federal government and the growth of Washington, D.C., Prince George’s County developed into a suburban community, with significant residential and commercial growth during the 20th century.
Major Highways and Landmarks
The county is well-connected by major highways, including the Capital Beltway (I-495), U.S. Route 50, and the Baltimore-Washington Parkway (MD 295). These routes facilitate access to Washington, D.C., and Baltimore, contributing to the county’s role as a crucial commuter area. Landmarks in Prince George’s County include the University of Maryland, College Park, which is the state’s flagship university, and the National Harbor, a large waterfront development along the Potomac River. The county is also home to FedExField, the stadium for the Washington Commanders, and the NASA Goddard Space Flight Center, a major research laboratory for space exploration.
3. Baltimore County
County Seat: Towson
- Area: 682 square miles
- Population: Approximately 854,535
- Area Codes: 410, 443, 667
- Latitude and Longitude: 39.4648° N, 76.5290° W
Location and History
Baltimore County is located in the northern part of Maryland, surrounding but not including the independent city of Baltimore. The county was established in 1659 and has a rich history tied to the development of the Baltimore metropolitan area. Initially, Baltimore County was an agricultural region, but with the growth of Baltimore City as a major port and industrial center, the county developed into a suburban area with diverse communities. The county’s growth accelerated in the 20th century with the rise of automobile commuting and suburban living.
Major Highways and Landmarks
Key highways running through Baltimore County include Interstate 695 (the Baltimore Beltway), Interstate 83, and U.S. Route 40. These roads connect the county to Baltimore City, Washington, D.C., and Pennsylvania, supporting its role as a suburban and commercial hub. Significant landmarks in Baltimore County include the historic Hampton National Historic Site, the scenic Gunpowder Falls State Park, and the bustling Towson Town Center, one of the largest shopping malls in the region. The county is also home to several prestigious institutions, such as Goucher College and Towson University.
4. Anne Arundel County
County Seat: Annapolis
- Area: 588 square miles
- Population: Approximately 590,336
- Area Codes: 410, 443, 667
- Latitude and Longitude: 38.9921° N, 76.5356° W
Location and History
Anne Arundel County is located in central Maryland, bordering the Chesapeake Bay to the east. The county was established in 1650 and named after Lady Anne Arundell, the wife of Cecilius Calvert, the second Lord Baltimore. Annapolis, the county seat, has a rich history as the capital of Maryland and as a significant colonial port. It also served as the temporary capital of the United States from 1783 to 1784. Over time, Anne Arundel County evolved from a largely agricultural region into a suburban area with a strong maritime industry.
Major Highways and Landmarks
The county is well-served by major highways such as Interstate 97, U.S. Route 50, and Maryland Route 2, which facilitate travel to Baltimore, Washington, D.C., and the Eastern Shore. Annapolis, known for its historic downtown and waterfront, is home to the United States Naval Academy and the Maryland State House, the oldest state capitol still in continuous legislative use. Other notable landmarks include the scenic Sandy Point State Park, which offers stunning views of the Chesapeake Bay, and the Arundel Mills shopping and entertainment complex.
5. Baltimore City
County Seat: Independent city (no county seat)
- Area: 92 square miles
- Population: Approximately 585,708
- Area Codes: 410, 443, 667
- Latitude and Longitude: 39.2904° N, 76.6122° W
Location and History
Baltimore City, an independent city not part of any county, is located in the central part of Maryland, along the Patapsco River, an arm of the Chesapeake Bay. Founded in 1729, Baltimore became a major seaport and industrial center during the 19th century, playing a crucial role in the War of 1812 and the Civil War. The city has a rich cultural and historical heritage, with strong ties to the maritime industry, African American history, and the arts. Over the 20th century, Baltimore evolved into a center for healthcare, education, and tourism, despite facing challenges such as deindustrialization and population decline.
Major Highways and Landmarks
Baltimore is served by several major highways, including Interstate 95, which runs along the East Coast, Interstate 83, and the Baltimore Beltway (I-695). These highways make the city accessible from Washington, D.C., Philadelphia, and New York. Key landmarks in Baltimore include the Inner Harbor, a historic seaport and popular tourist destination; Fort McHenry, the birthplace of the U.S. national anthem; and the National Aquarium, one of the country’s top aquariums. The city is also home to Johns Hopkins University and Hospital, renowned globally for medical research and education.
6. Howard County
County Seat: Ellicott City
- Area: 254 square miles
- Population: Approximately 334,529
- Area Codes: 410, 443, 667
- Latitude and Longitude: 39.2792° N, 76.8394° W
Location and History
Howard County, located in central Maryland, is bordered by Baltimore and Montgomery counties. It was established in 1851 and named after John Eager Howard, a Revolutionary War hero and former Governor of Maryland. The county’s history is closely tied to its agricultural roots, but in the latter half of the 20th century, it became known for its planned community of Columbia, which was developed in the 1960s as a new model of suburban living. Columbia brought rapid growth and transformed Howard County into one of the wealthiest counties in the nation.
Major Highways and Landmarks
Howard County is accessible via major highways such as Interstate 95, U.S. Route 29, and Maryland Route 32, which connect the area to Baltimore, Washington, D.C., and other key regions. The county is known for its affluent communities and quality of life, with landmarks including the historic Ellicott City, which boasts a charming downtown area with shops and restaurants, and Merriweather Post Pavilion, a popular outdoor concert venue. Columbia, with its well-planned neighborhoods, parks, and recreational facilities, remains a highlight, embodying the county’s modern suburban appeal.
7. Frederick County
County Seat: Frederick
- Area: 667 square miles
- Population: Approximately 296,113
- Area Codes: 240, 301
- Latitude and Longitude: 39.4143° N, 77.4105° W
Location and History
Frederick County is located in the northern part of Maryland, bordering Pennsylvania to the north and Virginia to the south. Established in 1748, the county has a rich history tied to its role as a strategic location during the Civil War, with the Battle of Monocacy being fought near the county seat, Frederick, in 1864. Frederick County has historically been an agricultural region, known for its dairy farming, orchards, and later, viticulture. Over the years, the county has seen significant growth, transitioning from a rural to a more suburban character, particularly in areas closer to Washington, D.C., and Baltimore.
Major Highways and Landmarks
Frederick County is well-connected by major highways, including Interstate 70, which runs east-west through the county, and Interstate 270, which connects Frederick to the Washington, D.C., metropolitan area. U.S. Route 15 also provides a key north-south route through the county. Notable landmarks in Frederick County include the historic downtown Frederick, known for its well-preserved 19th-century architecture and vibrant arts scene, the National Museum of Civil War Medicine, and Catoctin Mountain Park, which offers outdoor recreation and is home to the presidential retreat, Camp David. The county is also home to several wineries and the scenic Monocacy National Battlefield.
8. Harford County
County Seat: Bel Air
- Area: 527 square miles
- Population: Approximately 256,924
- Area Codes: 410, 443, 667
- Latitude and Longitude: 39.5505° N, 76.3436° W
Location and History
Harford County is situated in the northeastern part of Maryland, bordering the Susquehanna River and the Chesapeake Bay. The county was established in 1773 from parts of Baltimore County and named after Henry Harford, the illegitimate son of Frederick Calvert, the last Proprietor of Maryland. Harford County has a diverse history, with its early economy based on agriculture, shipbuilding, and trade. The county played a role in the War of 1812, with Havre de Grace, a key town, being burned by British forces. In the 20th century, the county became increasingly suburbanized, particularly as part of the Baltimore metropolitan area.
Major Highways and Landmarks
Harford County is served by major highways, including Interstate 95, which runs along the East Coast, and U.S. Route 1, a historic highway that parallels I-95 through the county. These highways connect Harford County to Baltimore, Philadelphia, and other major cities. Significant landmarks in Harford County include the Susquehanna State Park, offering scenic views and outdoor activities along the Susquehanna River, and the historic town of Havre de Grace, known for its maritime museums and waterfront. The Aberdeen Proving Ground, a U.S. Army facility, is also a major presence in the county, contributing to both the local economy and the national defense.
9. Carroll County
County Seat: Westminster
- Area: 453 square miles
- Population: Approximately 173,353
- Area Codes: 410, 443, 667
- Latitude and Longitude: 39.5645° N, 77.0229° W
Location and History
Carroll County is located in the northern central part of Maryland, bordering Pennsylvania to the north. The county was established in 1837 from parts of Baltimore and Frederick counties and was named after Charles Carroll of Carrollton, a signer of the Declaration of Independence. Historically, Carroll County was an agricultural region, known for its grain and dairy farms. Over time, the county developed a mix of rural, suburban, and small-town communities. The Battle of Westminster, part of the Gettysburg Campaign during the Civil War, took place in the county, underscoring its historical significance.
Major Highways and Landmarks
Major highways in Carroll County include Maryland Route 140, which connects Westminster to Baltimore, and Maryland Route 30, which provides access to Pennsylvania. Carroll County is known for its scenic landscapes, historic sites, and small-town charm. Notable landmarks include the Carroll County Farm Museum, which showcases the county’s agricultural heritage, and the historic Union Mills Homestead, a preserved 18th-century mill and homestead. The county seat, Westminster, features a charming downtown with shops, restaurants, and cultural attractions like the Carroll Arts Center. The annual Maryland Wine Festival, held in Westminster, is another highlight, attracting visitors from across the region.
10. Wicomico County
County Seat: Salisbury
- Area: 400 square miles
- Population: Approximately 104,551
- Area Codes: 410, 443, 667
- Latitude and Longitude: 38.3942° N, 75.6674° W
Location and History
Wicomico County is located in the southeastern part of Maryland on the Delmarva Peninsula. The county was established in 1867, carved out from parts of Somerset and Worcester counties, and named after the Wicomico River, which flows through the county. Salisbury, the county seat, has historically been a center for trade and commerce due to its strategic location at the head of the Wicomico River, which provided access to the Chesapeake Bay. The county’s economy has traditionally been based on agriculture, particularly poultry farming, and has diversified over the years to include manufacturing and services.
Major Highways and Landmarks
Wicomico County is served by major highways such as U.S. Route 50, which runs east-west across the Delmarva Peninsula, and U.S. Route 13, which runs north-south and connects the county to the rest of the peninsula. Salisbury, the largest city on the Eastern Shore, is a key commercial and cultural hub. Notable landmarks in Wicomico County include the Ward Museum of Wildfowl Art, which features an extensive collection of decoys and wildlife art, and Pemberton Historical Park, which offers trails and historic buildings. The Salisbury Zoo, known for its diverse animal exhibits, and the annual National Folk Festival, hosted in Salisbury, are also significant attractions.
List of All Counties in Maryland Alphabetically
Below please see all Maryland counties which are listed in alphabetical order.
- Allegany County, MD
- Anne Arundel County, MD
- Baltimore County, MD
- Calvert County, MD
- Caroline County, MD
- Carroll County, MD
- Cecil County, MD
- Charles County, MD
- Dorchester County, MD
- Frederick County, MD
- Garrett County, MD
- Harford County, MD
- Howard County, MD
- Kent County, MD
- Montgomery County, MD
- Prince George’s County, MD
- Queen Anne’s County, MD
- Saint Mary’s County, MD
- Somerset County, MD
- Talbot County, MD
- Washington County, MD
- Wicomico County, MD
- Worcester County, MD
Map of Maryland Counties
