Mcmillen rhymes with:
macmillan, mcmillan, mcmillon, macmillan, mcmillan, mcmillon, macmillan, mcmillan, mcmillon, macmillan, mcmillan, mcmillon, millan, millen, millin, millon
Mcmillen sounds like:
macmillan, macmullen, maximilian, mcmillan, mcmillian, mcmillin, mcmillion, mcmillon, mcmullan, mcmullen, mcmullin, muskmelon