"[1] At CCM Magazine, Grace S. Aspinwall gave the album a three-out-of-five-stars, calling this "a good project with many cheerful moments.

He carries a strong message with his folk-pop, coffee house style that made him famous on American Idol.

"[3] Cross Rhythms' Stephen Curry affirmed that "All the songs here show a positive faith in God who can tackle any problem", which he rated the album six-stars-out-of-ten, and called the effort "a thoughtful and well produced pop album though in places it struggles to show sufficient distinctiveness to rise above the welter of pop releases.

[5] Jesus Freak Hideout's Tincan Caldwell gave the album a three-and-a-half-out-of-five-stars, noting that "Only A Mountain fits sonically with other Idol alumnus' albums (that is to say, the music is mostly 'safe' pop and designed to appeal to the widest possible audience), but still shines brightly in spots and points to Castro having a long career ahead of him.

"[6] New Release Tuesday's Dawn Teresa gave the album a four-and-a-half-out-of-five-stars, proclaiming that "Jason Castro has always had a strong, original voice.