How do you find audition songs?

I’m a junior and a bass-baritone looking to double major in college in math and classical vocal performance. I’ve been looking at the audition requirements for various schools and have asked my friends who are music majors when did they start preparing and they told me Spring of their junior year. I want to start preparing soon but I don’t know how to find audition songs. Should I buy collections of art songs or where do I find audition pieces? I’m currently considering using a song from Jonathan Dove’s Three Tennyson Songs (Dark House), but that is an English language piece and I need a greater repertoire. Where should I start looking?

Do you have a vocal teacher or choir director that might have some suggestions for you in your range? Both my kids that auditioned for vocal were working closely with vocal teachers that helped select music specific for their ability and range. You may consider trying to find someone to help you through the prep and process. My 2nd kid had a compact list of 4 songs that covered the safer schools she was considering and then added schools from there. My older kid had something like 6 songs to cover a lot of bases and that was a lot. So make sure you’re checking requirements for schools of interest, some have very fussy requirements.

My younger kid had an english art song, an italian piece, a German piece and a legit MT song (which is optional a lot of places). That covered a lot of bases. The other thing is you can pull rep you have done previously.

I noticed DePaul vocal has a short list of faculty selected songs for UG auditions, you might dig around to find other lists.
https://music.depaul.edu/admission/auditions/undergraduate/Pages/voice.aspx

My oldest kid was a double degree student. If you are interested in double degree (double major is probably different at most schools if you were pursuing like 2 BA degrees which may not require an audition or maybe an audition for music scholarships but not program entry) be sure to talk to faculty about that if you have sample lessons. In our experience, some schools tout their double degree programs but individual faculty members may not prefer performance students taking that path. If you post what schools you are interested in, someone may have thoughts.

My son is a junior and a bass-baritone too! A lot of schools will want to see an Italian song, so you may want to look in 24 Italian Songs and Arias. Hal Leonard’s Lieder Anthology has many German songs to choose from, likewise French songs in their French Song Anthology. Even if you don’t own the books, you can see the table of contents on the Hal Leonard website and start listening to some songs. Italian is a language that everyone likes to see, but whether you want a French or a German song might depend on your familiarity with the languages. One of my son’s voice teachers is very enthusiastic about Aaron Copland songs being engaging for teenagers to sing. It is useful to figure out early whether you like your songs well enough to hear yourself sing them over and over again. You want to make sure you’re singing songs with varying tempos. A voice teacher (maybe your choir teacher at school if you’re not taking private lessons) can probably help you find songs that are suitable for your level of experience so you don’t get in the weeds on something that’s more complicated than it sounds. A voice professor we talked to said that a lot of high school students audition with songs that are too complex, and they’d rather hear something simpler sung really well.