The highway system of Hamilton County, New York, comprises 474.5 miles (763.6 km) of roads maintained by the New York State Department of Transportation (NYSDOT), the county, and its towns and villages.

The 94.5-mile (152.1 km) system, maintained by the Hamilton County Department of Public Works, connects the state routes to a number of small hamlets and other points of interest.

It stretches from Deposit in the Southern Tier to an intersection with NY 9N in Hague on the shores of Lake George.

[11] The stretch in Hamilton County is 43.30 miles (69.68 km) long, passing through mostly rural territory.

[12] NY 8 was assigned as part of the 1930 renumbering of state highways in New York and has not been changed within Hamilton County since that time.

[6] NY 10 is the shortest state route that traverses Hamilton County.

At 14.51 miles (23.35 km) long, its only intersection in the county is its northern terminus at NY 8.

The route passes through rural regions of Hamilton County and encounters no villages or noteworthy locations until Arietta.

[8][9] NY 28 is a scenic, rural highway that runs for 49.08 miles (79 km) from the Herkimer County line northeast of the NY 12 intersection to the Warren County line near Blue Mountain Lake.

Concurrent with the latter highway, NY 28N heads northward through mountainous parts of Hamilton County to Long Lake, where NY 30 splits and heads in the direction of Franklin County.

From here, NY 28N heads eastward, passing some mountains before entering Essex County and continuing into Newcomb.

[2] Initially, NY 30 was not the longest state highway in Hamilton County.

[6] NY 365 is the only post-1930 state route that once entered Hamilton County, but no longer does.

[17][18] NY 365 was truncated in the late 1950s to end near the Oneida County village of Holland Patent, eliminating a series of overlaps between NY 365 and other state routes that collectively extended from Holland Patent to Plattsburgh, Clinton County.

Route numbers, lengths, and termini are derived from the 2010 NYSDOT Hamilton County inventory unless otherwise noted.