The Purple Raiders received one of five bids reserved for independents and non-automatic qualifying conferences to enter the 36-team NCAA Tournament field.
Mount Union, in its second varsity season, is 15-2 overall and won the Ohio Athletic Conference regular season and tournament titles.
It is the first year that the nation's third oldest athletic conference -- the 112-year old OAC -- sponsored a women's lacrosse championship.
Keuka, located in the Finger Lakes region of Western New York, is making its second overall and second straight NCAA Tournament appearance after winning the Northeastern Athletic Conference title and its automatic bid.
The Storm is 16-2 overall and enter the NCAA Tournament on a 14-game win streak.
The winner of this matchup advances to a second round matchup Saturday at No. 1 ranked Cortland State (N.Y.).