  monroe county is a county located in the u.s. state of new york. as of 2013, the population was 749,606. its county seat is the city of rochester. the county is named after james monroe, fifth president of the united states of america. monroe county is part of the rochester, ny metropolitan statistical area. monroe county is located in western new york. ==history== when counties were established in the province of new york in 1683, the present monroe county was part of albany county. this was an enormous county, including the northern part of new york state as well as all of the present state of vermont and, in theory, extending westward to the pacific ocean. this county was reduced in size on july 3, 1766 by the creation of cumberland county, and further on march 16, 1770 by the creation of gloucester county, both containing territory now in vermont. on march 12, 1772, what was left of albany county was split into three parts, one remaining under the name albany county. one of the other pieces, tryon county, contained the western portion (and thus, since no western boundary was specified, theoretically still extended west to the pacific). the eastern boundary of tryon county was approximately five miles west of the present city of schenectady, and the county included the western part of the adirondack mountains and the area west of the west branch of the delaware river. the area then designated as tryon county now includes 37 counties of new york state. the county was named for william tryon, colonial governor of new york. in the years prior to 1776, most of the loyalists in tryon county fled to canada. in 1784, following the peace treaty that ended the american revolutionary war, the name of 
1821_establishments_in_New_York Monroe_County,_New_York New_York_counties Populated_places_established_in_1821 Rochester,_New_York_metropolitan_area