As part of efforts to achieve campus carbon neutrality by 2035, Cornell University launched the Earth Source Heat (ESH) project in 2007, to research the possibility of using deep geothermal heating to heat the campus. To effectively explore the availability of geothermal resources and the feasibility of extracting such resources, an accurate understanding of geologic features and regional seismicity is required. However, national and regional seismic networks do not have sufficient sensitivity to record seismicity in Tompkins County, NY. Thus, two seismic networks were installed to study the background seismicity in Tompkins County in advance of any proposed drilling as part of ESH. The first network (CorNET16) operated between 2015-2016 with 12 seismometers, while the current network installed from July 2019-present (CorNET21) includes 17 seismometers over a larger area. The installation of CorNET21 and analysis is completed under contract with Weston Geophysical Group with assistance from Cornell students, staff, and faculty. Preliminary analysis indicates about 359 seismic events in Tompkins County between August 2019-January 2021, including impulsive ground vibrations such as drilling, mine blasts, construction activities, as well a natural events such as microearthquakes. About 70 events were reviewed by a seismologist and a more accurate location was determined. Some natural microearthquakes have been observed, and efforts to separate these from the human-caused seismic events are ongoing. Events as small as magnitude negative 2 have been detected, but further work to assess the magnitudes and what small magnitude events might be missed is in progress. Re-analysis of the CorNET16 data using the same techniques used for CorNET21 finds about 20 seismic events in Tompkins County between 2015-2016 with the number of events and locations focused near or under Cayuga Lake similar to previous work. We suspect that more events were found by CorNET21 because of its increased sensitivity as well as change in the nature of seismic events. CorNET21 indicates dozens of seismic events each year within 10 km of the proposed geothermal drill site not visible in the national and regional seismic networks. Thus CorNET21 provides important information not otherwise available about local seismic events.