On

Harlem River Blues

, Justin Townes Earle pursues two contradictory impulses. It's a New York album, with songs about a subway driver for the Metropolitan Transit Authority, about "One More Night in Brooklyn," about drowning in the body of water that provides the album's title. But it's full of "Southern American Music," which is how Earle describes what he does: The roots of the songs extend directly to gospel blues, Sun Records rockabilly, Hank Williams country, Woody Guthrie folk, or Muscle Shoals soul.

"I tend to try to run the full gamut from blues, gospel, country, bluegrass, jazz; I just try to get a little bit of everything in there," Earle says. "I'm kind of mixed up."

But although Harlem River Blues, his third record, travels through many musical styles, it doesn't sound like a set of style exercises.

"That's the hardest part: trying to connect all those genres without making it seem like you forced ill-fitting puzzle pieces," he says, talking while on the road somewhere in Texas.

Earle has lived in New York for the last three years or so ("I spend so much time on the road, I'm not really sure how long"), but the son of Steve Earle "grew up in a mostly black neighborhood in Nashville, Tennessee." He comes honestly to Harlem River Blues' intersection of contemporary N.Y.C. stories with traditional Southern genres. While the genres are diverse, the album is coherent; it's excellent.

"My goal is to always bend what I see and what I do into existing formats. I think that's the challenge of most good singer-songwriters," he says. "I think good singer-songwriters realize that your chances of coming up with an original format is one in a million and that what we have, we have to work with. Part of being a songwriter is making things your own and bringing them into your head space."

Earle's head space has been mixed up, too. Like his father, he has struggled with substance abuse, and he canceled a Philly appearance early this fall when he halted a tour to enter voluntary rehab.

"It's a hazard of life for me. I don't have to be on the road; it can happen to me anywhere. I have a long history of substance abuse. I use drugs when I'm happy, I use drugs when I'm sad; it doesn't matter. I've been clean for a couple months now, though."

His trio, with Josh Hedley on fiddle and Bryn Davies on upright bass, now comes to the First Unitarian Church on Thursday. The sultry Jessica Lea Mayfield, whose second album arrives in February, opens.

Justin Townes Earle and Jessica Lea Mayfield play 8 p.m. Thursday at the First Unitarian Church, 2125 Chestnut St. Tickets: $13. Information: 215-821-7575; www.r5productions.com.