Onderdonk was a three-time IWLCA All-American. She earned second team honors in 1991 and moved up to the first team in 1992 and 1993. As a senior, Onderdonk led the Herons to a 15-2 overall record and an appearance in the NCAA tournament national championship game. A defender, she scored eight goals and notched three assists for 11 points. That year the William Smith defense limited five opponents to five goals or less. In 1992, the Herons went 15-1 advancing to the national championship game. Onderdonk posted a goal and four assists. William Smith limited its opponents to seven goals or less in every game, holding them to four goals or less 14 times. In 1991, Onderdonk scored one goal. The Herons went 15-2 and made it to the NCAA tournament championship round. Onderdonk finished her career with 13 goals and 10 assists for 23 points.
