Dennison was a two-time All-American, once in the 800 meters and again as a part of a distance medley relay squad. She twice represented Cornell at the NCAA championships. In 1996, she qualified for the NCAA finals in the 800 with a time of 2:09.17, which earned her an All-America honor. In 1997, she earned her second All-America honor as part of the indoor distance medley relay team that took fourth in the NCAA championship meet with a time of 11:14.76, setting a school record. The indoor middle distance relay squad was the only representative of the Cornell women's team at the NCAA championships that year. She took first place at the 1997 indoor Heps championships in the 800 meters with a time of 2:10.10, which also earned her first-team All-Ivy honors. A four-year letter winner, Dennison was the recipient of the Theodota Ladas Award as the best middle distance runner at Cornell as a senior.
