Hare Krsna
Please accept my humble obeisance. All glories to Srila Prabhupada
Brahma-vaivarta Purana
Canto four, chapter seventeen, texts 217-220
tasya namantaram vrnda tad idam ca tapo-vanam
tena vrndavanam nama pravadanti manisinah
Another name of Tulasi is Vrinda. For this reason, the wise say that Vrindavan is named after Tulasi because she performed austerities there.
athava te pravaksyami param hetv-antaram srnu
yena vrndavanam nama punya-ksetrasya bharate
Please listen and I will tell you stil