Amateur poetry anthologies are held by few libraries, and are rarely available for sale on the shelves of brick-and-mortar bookstores. Most amateur poetry publishers, especially vanity presses, sell their anthologies directly to winning contest entrants, and do not market their publications to libraries or bookstores. On occasion, a library will acquire an anthology at the request of a library member whose work is published in it, or a bookstore will agree to carry one or two hard copies at the request of a customer. The Library of Congress itself holds several hundred amateur poetry anthologies, most published between 1980-2000. Many of them are now available in a special Amateur Poetry Anthologies Reference Collection on Deck 7 of the Library's Main Reading Room.
To identify whether the Library of Congress, or another library, holds a copy of an amateur poetry anthology, you can search the WorldCat database External, a global library catalog that lists materials held by thousands of libraries around the world. WorldCat's Advanced Search External page allows users to search for materials using a variety of criteria, including author, title, ISBN, publication date, and keyword. If you locate a record for an amateur poetry anthology through WorldCat, you can enter your zip code or location in the record's "Enter your location" box to bring up a list of libraries that should hold the book. You, or a librarian at your local library, can then contact the holding library to see whether its copy of the anthology includes your poem.
If you would like to purchase a copy of an amateur poetry anthology, your best option is usually to check for copies available through bookstore databases such as AddALL Used Books and Out-of-Print Book Finder External, Amazon.com External, and BookFinder.com External. If the anthology publisher is still active, you can contact the publisher directly to see if it is possible to purchase a copy through it.