Otis lies in the southern end of the Berkshire Mountains, and is dotted by several hills. The West Branch of the Farmington River rises in the town, heading southward towards the Connecticut River. The southeastern part of town is dominated by the Otis Reservoir and Big Pond, as well as portions of Tolland State Forest and Otis State Forest. The highest points in the town are to the north, with Church Hill to the east and Kingsbury Mountain to the west. Much of the land around the brooks of town are marshy. Just west of the town center is Otis Ridge Ski Area. Most of the population is around the reservoir and the center of town.
Otis lies at the intersection of Route 8 and Route 23. Route 8 was once part of the New England interstate system, as the Stratford-Waterbury-North Adams Route. Route 23 is known as the Knox Trail, with a historical marker along the route in the eastern part of town. Interstate 90 (also known as the Massachusetts Turnpike) passes through the norhtern edge of town twice, with the nearest exit being in Lee. There is no rail, bus or air service in town, with the nearest being in Pittsfield and Westfield. The nearest national air service is at Bradley International Airport in Windsor Locks, Connecticut.
As of the census of 2000, there were 1,365 people, 567 households, and 386 families residing in the town. By population, Otis ranks 19th out of the 32 cities and towns in Berkshire County, and 312nd out of 351 cities and towns in Massachusetts. The population density was 38.1 people per square mile (14.7/km²), which ranks it 18th in the county and 312th in the Commonwealth. There were 1,572 housing units at an average density of 43.9/sq mi (16.9/km²). The racial makeup of the town was 96.56% White, 0.59% African American, 0.29% Native American, 0.88% Asian, 0.37% from other races, and 1.32% from two or more races. Hispanic or Latino of any race were 0.29% of the population.
There were 567 households out of which 26.6% had children under the age of 18 living with them, 59.1% were married couples living together, 5.5% had a female householder with no husband present, and 31.9% were non-families. 24.3% 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 2.40 and the average family size was 2.90.
In the town the population was spread out with 21.8% under the age of 18, 5.7% from 18 to 24, 28.1% from 25 to 44, 30.3% from 45 to 64, and 14.1% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 111.6 males. For every 100 females age 18 and over, there were 108.2 males.
The median income for a household in the town was $51,488, and the median income for a family was $55,455. Males had a median income of $41,065 versus $30,179 for females. The per capita income for the town was $25,029. About 4.6% of families and 7.4% of the population were below the poverty line, including 11.4% of those under age 18 and 4.2% of those age 65 or over.
Otis uses the open town meeting form of government, and is led by a board of selectmen and an administrative assistant. All four of the town's main offices, including the town hall, police and fire departments and the town library, are all located at the center of town, as is the central post office. A second post office is located in East Otis. The library is a part of the regional library systems. The nearest hospital, Noble Hospital, is twenty miles away in Westfield.
On the state level, Otis is represented in the Massachusetts House of Representatives by the Fourth Berkshire district, which covers southern Berkshire County, as well as the westernmost towns in Hampden County. In the Massachusetts Senate, the town is represented by the Berkshire, Hampshire and Franklin district, which includes all of Berkshire County and western Hampshire and Franklin Counties. The town is patrolled by the First (Lee) Station of Barracks "B" of the Massachusetts State Police.
On the national level, Otis is represented in the United States House of Representatives as part of Massachusetts's 1st congressional district, and has been represented by John Olver of Amherst since June 1991. Massachusetts is represented in the United States Senate by senior Senator Ted Kennedy and junior Senator John Kerry.
The nearest community college is Berkshire Community College in Pittsfield and Great Barrington. The nearest state college is Westfield State College, and the nearest state university is the University of Massachusetts Amherst. The nearest private college is Bard College at Simon's Rock in Great Barrington, with other private colleges in Springfield.