New Haven was the last town taken from Mexico before the organization of Oswego County. It was originally formed 2nd April, 1813 including the lots 24 - 27, about ½ mile wide strip of land running along the lake shore including the mouth of Salmon River. This strip was taken from New Haven in 1836 by Law and annexed to Mexico. This left New Haven with its present area of 18,303 acres. It is the smallest town in the County being 5 miles east & west by 5 3/4 miles north & south, with a total of 133 lots.
The town has three creeks; Spring Brook, Catfish, and Butterfly flowing northerly into Lake Ontario. Butterfly and Lilly Marshes give the town extensive swamp area.
Early settlers around 1800 found dense wilderness and heavy timbers of hardwoods. As settlers fell the forests, agriculture gained attention, especially dairying and fruit growing. The first road in the Town was opened sometime before 1806. By 1814 there were 12 road districts. In 1844 the Oswego & Rome Plank Road was begun, passing through New Haven making it a busy thorough fare. By 1895 the town had 66 Road Districts with a path master or highway overseer of each. The railroad came to the town in 1865 running midway between New Haven Village and Lake Ontario, the station being at Demster. During the 1870’s - 1920’s the settlement of Demster thrived.
The first Town meeting was held at the home of Ansel Snow in the Village of New Haven on 14 April 1814 with 66 votes being cast. David Easton was the first Supervisor and Jonathan Wing the first Town Clerk. The first permanent settler of New Haven was Solomon Smith. He located at lot 47 in 1800 building the first log house. In 1812 he built the first framed dwelling. The next known inhabitants to New Haven were Capt. Wyman and Eleozer Snow who came in 1804 from Madison County. Capt. Wyman erected the 3rd log house on lot 57 near the east end of the old Barker farm (presently near Dempster Camp Ground). New Haven Village was called “Gay Head” but in 1819 was changed to the present name, New Haven.