|Lyndon, New York|
|— Town —|
|Motto: Rainbow Skys, Fields and Streams|
|• Total||33.3 sq mi (86.1 km2)|
|• Land||33.2 sq mi (86.0 km2)|
|• Water||0.1 sq mi (0.1 km2)|
|Elevation||1,978 ft (603 m)|
|• Density||21/sq mi ( 8.2/km2)|
|Time zone||Eastern (EST) (UTC-5)|
|• Summer (DST)||EDT (UTC-4)|
|GNIS feature ID||0979174|
The town was first settled around 1806. The Town of Lyndon was founded in 1829, formed from the Town of Franklinville. The town was briefly called "Elgin" around 1857.
In 1875, the population of Lyndon was 805.
According to the United States Census Bureau, the town has a total area of 33.3 square miles (86 km2), of which, 33.2 square miles (86 km2) of it is land and 0.1 square miles (0.26 km2) of it (0.15%) is water.
The Town of New Hudson in Allegany County is to the east. The north town line is shared by Town of Farmersville, and the south town line is shared with the Town of Ischua. The Town of Franklinville is west of Lyndon.
At the 2000 census, there were 661 people, 250 households and 187 families residing in the town. The population density was 19.9 people per square mile (7.7/km²). There were 639 housing units at an average density of 19.2 per square mile (7.4/km²). The racial makeup of the town was 97.28% White, 0.61% African American, 1.21% Native American, and 0.91% from two or more races. Hispanic or Latino of any race were 0.76% of the population.
There were 250 households of which 33.2% had children under the age of 18 living with them, 60.0% were married couples living together, 7.2% had a female householder with no husband present, and 25.2% were non-families. 18.0% of all households were made up of individuals and 7.6% had someone living alone who was 65 years of age or older. The average household size was 2.64 and the average family size was 2.98.
Age distribution was 27.7% under the age of 18, 6.2% from 18 to 24, 30.6% from 25 to 44, 25.3% from 45 to 64, and 10.3% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 101.5 males. For every 100 females age 18 and over, there were 110.6 males.
The median household income was $34,091, and the median family income was $37,361. Males had a median income of $29,063 versus $22,250 for females. The per capita income for the town was $15,054. About 6.7% of families and 12.6% of the population were below the poverty line, including 14.3% of those under age 18 and none of those age 65 or over.