Founded in 1802, St. Lawrence County is one of 62 counties in the state of New York. Historically, St. Lawrence County was formed from Clinton County, Herkimer County, and Montgomery County. The city of Canton is the county seat. With FIPS code of 89, St. Lawrence County has a population of 108,051 and area of 2,821 square miles (7,306 km2).
List of all cities in Saint Lawrence County, NY alphabetically
| City/Town | Postal Code | Area Code |
| Benson Mines, NY | 13690 | 315 |
| Brasher Falls, NY | 13613 | 315 |
| Brasie Corners, NY | 13642 | 315 |
| Brier Hill, NY | 13614 | 315 |
| Bucks Bridge, NY | 13617 | 315 |
| Canton, NY | 13617 | 315 |
| Chase Mills, NY | 13621 | 315 |
| Childwold, NY | 12922 | 518 |
| Chippewa Bay, NY | 13623 | 315 |
| Clare, NY | 13684 | 315 |
| Clarkson University, NY | 13699 | 315 |
| Colton, NY | 13625 | 315 |
| Cranberry Lake, NY | 12927 | 315 |
| Crary Mills, NY | 13617 | 315 |
| De Kalb Junction, NY | 13630 | 315 |
| De Peyster, NY | 13633 | 315 |
| Degrasse, NY | 13684 | 315 |
| Depeyster, NY | 13633 | 315 |
| Eben, NY | 13676 | 315 |
| Eddy, NY | 13617 | 315 |
| Edwards, NY | 13635 | 315 |
| Edwardsville, NY | 13646 | 315 |
| Elmdale, NY | 13642 | 315 |
| Emeryville, NY | 13642 | 315 |
| Fine, NY | 13639 | 315 |
| Fort Jackson, NY | 12965 | 315 |
| Fowler, NY | 13642 | 315 |
| Fullerville, NY | 13642 | 315 |
| Gouverneur, NY | 13642 | 315 |
| Grantville, NY | 13667 | 315 |
| Hailesboro, NY | 13645 | 315 |
| Hammond, NY | 13646 | 315 |
| Hannawa Falls, NY | 13647 | 315 |
| Hatchs Corner, NY | 13684 | 315 |
| Helena, NY | 13649 | 315 |
| Hermon, NY | 13652 | 315 |
| Heuvelton, NY | 13654 | 315 |
| Hewittville, NY | 13668 | 315 |
| Hopkinton, NY | 12965 | 315 |
| Knapps Station, NY | 13668 | 315 |
| Langdon Corners, NY | 13617 | 315 |
| Lawrenceville, NY | 12949 | 315 |
| Lisbon, NY | 13658 | 315 |
| Lower Oswegatchie, NY | 13670 | 315 |
| Macomb, NY | 13642 | 315 |
| Madrid, NY | 13660 | 315 |
| Madrid Springs, NY | 13660 | 315 |
| Massena, NY | 13662 | 315 |
| Massena Center, NY | 13662 | 315 |
| Massena Springs, NY | 13662 | 315 |
| Morley, NY | 13617 | 315 |
| Morristown, NY | 13664 | 315 |
| Natural Dam, NY | 13642 | 315 |
| Newton Falls, NY | 13666 | 315 |
| Nicholville, NY | 12965 | 315 |
| Norfolk, NY | 13667 | 315 |
| North Lawrence, NY | 12967 | 315 |
| North Russell, NY | 13617 | 315 |
| North Stockholm, NY | 13668 | 315 |
| Norwood, NY | 13668 | 315 |
| Ogdensburg, NY | 13669 | 315 |
| Oswegatchie, NY | 13670 | 315 |
| Parishville, NY | 13672 | 315 |
| Parishville Center, NY | 13676 | 315 |
| Piercefield, NY | 12973 | 518 |
| Pierces Corner, NY | 13642 | 315 |
| Pierrepont, NY | 13617 | 315 |
| Pope Mills, NY | 13654 | 315 |
| Potsdam, NY | 13676 | 315 |
| 13699 | 315 | |
| Pyrites, NY | 13677 | 315 |
| Raymondville, NY | 13678 | 315 |
| Red Mills, NY | 13669 | 315 |
| Rensselaer Falls, NY | 13680 | 315 |
| Richville, NY | 13681 | 315 |
| Rooseveltown, NY | 13683 | 315 |
| Rossie, NY | 13646 | 315 |
| Ruby Corner, NY | 13646 | 315 |
| Russell, NY | 13684 | 315 |
| Sandfordville, NY | 13676 | 315 |
| Sissonville, NY | 13676 | 315 |
| Slab City, NY | 13676 | 315 |
| Somerville, NY | 13642 | 315 |
| South Colton, NY | 13687 | 315 |
| South Edwards, NY | 13635 | 315 |
| South Russell, NY | 13684 | 315 |
| Star Lake, NY | 13690 | 315 |
| Waddington, NY | 13694 | 315 |
| Wanakena, NY | 13695 | 315 |
| West Parishville, NY | 13676 | 315 |
| West Pierrepont, NY | 13617 | 315 |
| West Potsdam, NY | 13676 | 315 |
| West Stockholm, NY | 13696 | 315 |
| Winthrop, NY | 13697 | 315 |
| Yaleville, NY | 13668 | 315 |