Love letters Loveland is the perfect place from which to send your Valentine’s Day cards and love letters. Send your stamped cards in a larger envelope to: Postmaster, Attention Valentines, 446 E. 29th St., Loveland, CO 80538-9998. You must have proper postage on all of your cards and letters. According to the Loveland Chamber of Commerce, senders can drop off their larger envelope, containing properly stamped cards, at any Colorado USPS Post Office (addressed to the Loveland Postmaster) with no additional postage required on the larger envelope.