The valley in which Cayuga Lake is located is long and narrow with a north-south orientation. Ithaca is at the southern end (the "head") of the lake, but the valley continues to the southwest behind the city. Originally a river valley, it was deepened and widened by the action of Pleistocene ice sheets over the last several hundred thousand years. The lake, which drains to the north, formed behind a dam of glacial moraine. The rock is predominantly Devonian and, north of Ithaca, is relatively fossil rich. Glacial erratics can be found in the area. The world-renowned fossils found in this area can be examined at the Museum of the Earth.
Ithaca was founded on flat land just south of the lake land that formed in fairly recent geological times when silt filled the southern end of the lake. The city ultimately spread to the adjacent hillsides, which rise several hundred feet above the central flats: East Hill, West Hill, and South Hill. Its sides are fairly steep, and a number of the streams that flow into the valley from east or west have cut deep canyons, usually with several waterfalls.
The natural vegetation of the Ithaca area, seen in areas unbuilt and unfarmed, is northern temperate broadleaf forest, dominated by deciduous trees.
Ithaca is in the rural Finger Lakes region about 225 miles (362 km) northwest of New York City; the nearest larger cities, Binghamton and Syracuse, are an hour's drive away by car, Rochester and Scranton are two hours, Buffalo and Albany are three. New York City, Philadelphia, Toronto, and Ottawa are about four hours away.
Ithaca lies at over a half hour's drive from any interstate highway, and all car trips to Ithaca involve some driving on two-lane state rural highways. The city is at the convergence of many regional two-lane state highways: Routes 13, 13A, 34, 79, 89, 96, 96B, and 366. These are usually not congested except in Ithaca proper. However, Route 79 between the I-81 access at Whitney Point and Ithaca receives a significant amount of Ithaca-bound congestion right before Ithaca's colleges reopen after breaks.
There is frequent intercity bus service by Greyhound Lines, New York Trailways, and Shortline (Coach USA), particularly to Binghamton and New York City, with limited service to Rochester, Buffalo and Syracuse, and (via connections in Binghamton) to Utica and Albany. The bus station serving all these companies is the former Delaware, Lackawanna & Western railway station on Meadow St. between W State and W Seneca streets, a little over half a mile west of downtown Ithaca. Cornell University runs a premium Campus to Campus bus between its Ithaca campus and its medical school in New York City which is open to the public.
Ithaca is the center of an extensive bus public transportation network. TCAT, Inc (Tompkins Consolidated Area Transit, Inc.) is a not-for-profit corporation that provides public transportation for Tompkins County New York. TCAT was reorganized as a non-profit corporation in 2004 and is primarily supported locally by Cornell University, the City of Ithaca and Tompkins County. TCAT's ridership increased from 2.7 million in 2004 to 4.4 million in 2013. https://web.archive.org/web/20141027015210/http://www.tcatbus.com/files/all/tcat_2013_yearbook_-_final.pdf TCAT operates 33 routes, many running seven days a week. It has frequent service to downtown, Cornell, Ithaca College, and the Shops at Ithaca Mall in the neighboring Town of Lansing, but less frequent service to many residential and rural areas, including Trumansburg and Newfield. Chemung County Transit (C-TRAN) runs weekday commuter service from Chemung County to Ithaca. Cortland Transit runs commuter service to Cornell University. Tioga County Public Transit operates three routes to Ithaca and Cornell, but will cease operating on November 30, 2014.
GADABOUT Transportation Services, Inc. provides demand-response paratransit service for seniors over 60 and people with disabilities. Ithaca Dispatch provides local and regional taxi service. In addition, Ithaca Airline Limousine and IthaCar Service connect to the local airports.
In July 2008, a non-profit called Ithaca Carshare began a carsharing service in Ithaca. Ithaca Carshare has a fleet of vehicles shared by over 1500 members as of July 2015 and has become a popular service among both city residents and the college communities. Vehicles are located throughout Ithaca downtown and the two major institutions. With Ithaca Carshare as the first locally run carsharing organization in New York State, others have since launched in Buffalo, Albany, NY, and Syracuse. Independent studies have shown that for each Ithaca Carshare vehicle in the fleet, 15 fewer personally owner cars are owned.
Rideshare services to promote carpooling and vanpooling are operated by ZIMRIDE and VRIDE. A community mobility education program, Way2Go is operated by Cornell Cooperative Extension of Tompkins County. Way2Go's website provides consumer information and videos. Way2Go works collaboratively to help people save money, stress less, go green and improve mobility options. The 2-1-1 Tompkins/Cortland Help line connects people with services, including transportation, in the community, by telephone and web on a 24/7 basis. The information and referral service is operated by the Human Services Coalition of Tompkins County, Inc. Together, 2-1-1 Information and Referral and Way2Go are a one-call, one-click resource designed to mobility services information for Ithaca and throughout Tompkins County.
As a growing urban area, Ithaca is facing steady increases in levels of vehicular traffic on the city grid and on the state highways. Outlying areas have limited bus service, and many people consider a car essential. However, many consider Ithaca a walkable and bikeable community. One positive trend for the health of downtown Ithaca is the new wave of increasing urban density in and around the Ithaca Commons. Because the downtown area is the region's central business district, dense mixed-use development that includes housing may increase the proportion of people who can walk to work and recreation, and mitigate the likely increased pressure on already busy roads as Ithaca grows. The downtown area is also the area best served by frequent public transportation. Still, traffic congestion around the Commons is likely to progressively increase.