Enya received mostly positive reviews and was a mild commercial success, reaching No. 69 in the UK. Following Enya's rise in popularity, the album was reissued as The Celts by Warner Music Group which reached No. 10 in the UK. The album has sold 1 million copies in the US.
The album includes only a portion of the music Enya composed for the documentary series. In 1992, coinciding with the reissue of the album, a previously unreleased track from these sessions, "Eclipse", was released as a B-side on the CD single for "the Celts". In 2005, another previously unreleased track from the same sessions, a "Spaghetti Western Theme" done in the style of Hugo Montenegro, was released on the CD single for "Amarantine", in memory of one of the producers of the TV series.
Filmmaker David Bickley reused music from the soundtrack later in The Memory of Earth, an installment in his documentary trilogy Mythological Lands. The song "Boadicea" was also used in the soundtrack of the 1992 American film Sleepwalkers. "Epona" appears in the 1991 Steve Martin romantic comedy L.A. Story.
The Fugees sampled "Boadicea" from this album for their song "Ready or Not" on 1996's The Score. Enya had prepared to sue the group for copyright infringement because they had not asked for permission and did not give her credit. After learning that The Fugees were not gangsta rappers, Enya declined to follow through with the suit, but stickers were then placed on The Score giving Enya credit for her work.Mario Winans also sampled "Boadicea" for the melody of the song "I Don't Wanna Know". Producer P. Diddy reportedly personally contacted Enya for permission and gave her 60 percent of the royalties. She also received name billing ("Mario Winans featuring Enya and P. Diddy") for the song, which turned out to be a hit, putting her name #2 on the Hot R&B/Hip-Hop Singles & Tracks chart in 2004. The song was also sampled on the answer-back song "You Should Really Know" by The Pirates featuring Shola Ama, Naila Boss & Ishani which peaked at #8 on the UK Singles Chart. "Boadicea" (with "Ready or Not") was also sampled by Nina Sky for their hype single "Time to Go" featuring Angie Martinez, from the mixtape presented by Cipha Sounds.
The title track was used as the theme music for the sports show Gaelic Games which aired in the UK on Channel 4 in the 1990s.
Italian hardstyle DJ Francesco Zeta's (Argese Francesco) 2008 song "Fairyland" made use of a sample from "Boadicea". In 2011 a small sample of "Boadicea" has been used in the song Der erste Winter by German singer Cassandra Steen, which has been released on the album Mir so nah. In 2012 she made another version, subtitled "ReAmp", which again utilised the sample. Also in 2012, hip hop artist Meek Mill sampled "Boadicea" on his mixtape Dreamchasers 2 on a song named after the Fugees' song, "Ready or Not".
In November 1992, following Enya's rise in popularity, the album reissued as The Celts with remastering by Arun Chakraverty and cover art by Sooky Choi and photography by David Scheinmann. The tracks have slightly different running times than the original release. "Portrait (Out of the Blue)", however, is an extended version previously released as "Out of the Blue", the B-side to Enya's 1988 single "Orinoco Flow".
In 2009, a remastered version of The Celts exclusive to Japan was released as a Limited Edition on SHM-CD with "Eclipse" as a bonus track.