The vast majority of TCAT bus routes are based in the City of Ithaca and surrounding urban area.

In the 1960s the City and Cornell established independent bus systems which expanded throughout the next two decades.

In 1974, a transit service in Northeast Ithaca (Lansing, Cayuga Heights and the Town of Ithaca) was started by apartment owners contracting with Swarthout Coaches to operate limited service for Cornell students, and as the public demand for service increased, the apartment owners sought assistance from local governments and Cornell University, which became Northeast Transit in 1978.

Tompkins County became involved in supporting suburban routes and in developing rural transit service.

The County formed TOMTRAN to extend fixed-route bus service to Dryden, Caroline and Newark Valley[7] in 1982, Groton (1983), Newfield and Ulysses (1985), and Lansing and Danby (1991).

[8] In 1996, the New York State Legislature adopted a state law authorizing that "the county of Tompkins, the city of Ithaca and Cornell University may jointly provide for mass transportation services in the county of Tompkins.

",[9] and on April 1, 1998, the City of Ithaca, Cornell University and Tompkins County established TCAT as a joint venture (public entity) to operate public transit service in Tompkins County, service began in 1999, establishing a unified route and fare system.

Inc. in 2005 with representatives of City of Ithaca, Cornell University, and Tompkins County serving on its board of directors.

TCAT's main hub is Green Street Station, off of the Commons, a two-block pedestrian mall in downtown Ithaca.

Most non South Hill routes run through the Cornell University campus; East Avenue and Tower Road near Uris and Statler Halls is considered a secondary hub.

Enfield Highway Department Green St. @ Commons ARR:Boyce Thompson Institute ARR:Dairy Bar DEP:Vet School Aubles Trailer Park Green St. @ Commons ARR:Boyce Thompson Institute DEP:Vet School Lansing Fire Company #3 ARR:Seneca St. @ Commons DEP:Green St. @ Commons Lansing School ARR:Boyce Thompson Institute DEP:Vet School Lake St. @ Ithaca High School Lansing Fire Station #4 ARR:Seneca St. @ Commons DEP:Green St. @ Commons Springbrook @ Farrell Lansing Town Hall ARR:Sage Hall DEP:Dairy Bar Groton Express Mart Seneca St. @ Commons Schwartz CPA

Seneca St. @ Commons Groton Express Mart Caroline Turnaround ARR:Seneca St. @ Commons DEP:Green St. @ Commons ARR:Vet School Ithaca Commons (Green St. @ Commons) – Brooktondale – Ellis Hollow – Varna – Cornell – Ithaca Commons (Seneca St. @ Commons) Ithaca Commons (Green St. @ Commons) – Cornell – Varna – Ellis Hollow – Brooktondale – Ithaca Commons (Seneca St. @ Commons) Hillview Terrace Mobile Home Park ARR:Seneca St. @ Commons DEP:Green St. @ Commons DEP:Aurora St. @ Commons ARR:Boyce Thompson Institute DEP:Vet School Newfield Central School Green St. @ Commons ARR:Boyce Thompson Institute DEP:Vet School Groton Express Mart The Shops at Ithaca Mall Green St. @ Commons TC3 Dorms The Shops at Ithaca Mall DEP:Green St. @ Commons ARR:Dairy Bar ARR:Boyce Thompson Institute DEP:Vet School (Early Morning) A Lot – Lower Stop Early Morning and Peak Time Only Dairy Bar (Peak Hours) East Hill Plaza A Lot – Lower Stop (Except Morning Peak) Hasbrouck (Morning Peak Only) Hasbrouck Apartments (Hasbrouck) – North Campus – Central Campus West Campus (Stewart @ University) – Central Campus (Uris Hall Across Street) Morning Peak Only Collegetown (Schwartz CPA) – Central Campus – North Campus (Robert Purcell Community Center) – Cradit Farm Dr. – Central Campus – Collegetown (Schwartz CPA) Night Service Only Hasbrouck Apartments (Hasbrouck) – North Campus – Thurston Ave – West Campus – Collegetown (Schwartz CPA) – Tower Rd – Maple Ave – East Hill Plaza (East Hill Plaza) Weekends Hasbrouck (Hasbrouck Apartments) – North Campus – Thurston Ave – West Campus – Collegetown (Schwartz CPA) – Maple Ave – East Hill Plaza – East Ithaca – Eastern Heights (Skyvue @ Snyder Hill) Night Time Only TCAT operates a mix of fifty-one 35 ft and 40 ft transit buses and three small 14-seat buses.