Back when we had no idea what the hell we were doing, when there’s bleed on all the instruments but there’s something so charming in the naiveté.”[6] Thematically, the album continues songwriter Matthew Milia's perennial obsession with his native environment of Metro Detroit.

Speaking to REVUE, Milia explained: “Metro Detroit is a very amorphously large and complex region of all these colliding communities and socioeconomic identities, and I’ve always been endlessly fascinated with how it all comes together.

So I just kind of endlessly investigate that in my songs.”[7] But as the first Frontier Ruckus album since Milia's getting married and becoming a father, On the Northline also evoked a deeper domestic introspection than ever.

"[9] The album received a warm critical reception, especially in the United Kingdom where the band embarked on a release tour supporting The Handsome Family.

A Metro Times cover story commented on the universal appeal of Milia's lyricism, despite their pertaining hyper-specifically to Michigan places and themes: “Based on the positive reactions to Northline’s three singles, it’s also clear that Frontier Ruckus’ dedicated fan base, even if they aren’t Michiganders, are still hungry for these mitten-state ruminations.”[10] KLOF Magazine commented on the record's balance of emotions by saying: "If adolescent melancholy and nostalgic yearning are both constants in the Frontier Ruckus musical firmament, then the redemptive power of love is still the star that shines brightest – especially when life can appear at its bleakest.