It’s a pretty familiar rite of passage: You’re within sight of age 30, or maybe a little past it, and the label “young adult” no longer seems applicable; somewhere along the way, for better or worse, you’ve become a full-fledged grown-up. Then the death of a family member ushers in a period of reflection and reminiscences of youth – a time that seems simultaneously closer and farther away than you might’ve thought.

For singer-songwriter Aoife O’Donovan, her grandfather’s passing at the end of 2013 elicited childhood memories rooted in Ireland as well as her native Greater Boston. This introspection came at a time when O’Donovan – a folk/acoustic music performer since her teens, a member of the groundbreaking progressive bluegrass band Crooked Still, and the “jazz-grass” supergroup Wayfaring Strangers (with a cast that included Tony Trischka, Andy Statman, John McGann, and Tracy Bonham), and a frequent soloist in “A Christmas Celtic Sojourn,” among other activities – had settled into a solo career, having released her first solo album, “Fossils,” earlier that year, and was considering her next project.

So O’Donovan distilled the various recollected images and sensations from many visits to her grandparents’ home in the small coastal town of Clonakility, Co. Cork, and over subsequent months interpolated them into a collection of new songs. These formed the basis of her second album, “In the Magic Hour,” which she released in January.

While nostalgia, and sadness over the loss of her grandfather, are both present on “In the Magic Hour,” the album is more a contemplation of memory itself, its interrelatedness to experience, and the transmutability of both throughout life. In this spirit of looking back while going forward, O’Donovan touches on her Irish roots and the Americana style that characterized a good chunk of her earlier work, but also continues to explore a more ambitious, indie-folk sound. The title track includes a jaunty Wurlitzer keyboard part (played by O’Donovan) that seems not far removed from a vintage Beach Boys record; “The King of All Birds” is enlivened by a boisterous string ensemble, clarinet, and trombone; and then there’s “Donal Óg,” a revered Irish lament of loss and remembrance, which here is given a new resonance with brooding, distorted electric guitars and a moving coda via a home recording of O’Donovan’s grandfather singing.

Last month saw O’Donovan – who moved to Brooklyn in 2009 (she also lived there for two years after graduating from New England Conservatory in 2003) – return to her old stomping grounds, as she performed at The Sinclair in Harvard Square. Coming to Boston to do gigs is not a novel experience for her, but until recent years these were largely in the context of Crooked Still and other bands, and productions such as “Christmas Celtic Sojourn” or the annual tour by fiddle ensemble Childsplay, for whom she was lead vocalist.

“On the one hand, it doesn’t matter where I’m performing – I’m just happy to present my music as a solo artist,” said O’Donovan by phone shortly before her date at The Sinclair. “But of course, it’s always nice to be back in Boston, not only because I grew up there but because it’s a big part of who I am musically.”

The formative musical experiences for O’Donovan began right in her Newton home, thanks to her parents Brian (WGBH “A Celtic Sojourn” host and festival/concert organizer) and Lindsay, a talented pianist and singer. In the O’Donovan household, music – Irish, American, folk, rock, classical – was not just something to listen to but to savor, and to experience with family and friends, many of whom were successful, accomplished musicians.

“I knew early on that music would be a big part of my life, and that was because of my parents – they always encouraged and supported me,” said O’Donovan. “And there were other adults, too – like my music teacher at Newton North High School, Mr. Travers – who helped me along the way. Having access to the amazing music community in Boston also was incredibly important: There were the Irish venues, like The Burren, but going to places like Passim, the Lizard Lounge and the Cantab got me more and more interested in bluegrass and other American music.

“Growing up in Boston was a great way to hone your musical chops.”

Those chops were on full display when Crooked Still came together in 2001, setting bluegrass convention on its head by putting Corey DiMario’s string bass and Greg Lizst’s five-string banjo – traditional bluegrass/string band instruments – alongside the mercurial cello of Rushad Eggleston, who would take solos or solidify the rhythm with equal aplomb. O’Donovan’s vocals – by turns ethereal and seductive – were the crowning touch, making for an urban, cosmopolitan take on a genre championed by the likes of Bill Monroe, Jimmy Martin and Earl Scruggs.

Crooked Still – which became a quintet after Eggleston’s departure in 2007, adding cellist Tristan Claridge and fiddler Brittany Haas – released five albums, then went on hiatus in 2012 as its members pursued other projects. The band played reunion concerts in 2014 and last year.

By the time Crooked Still adjourned, O’Donovan had already undertaken a host of ongoing and temporary collaborations, notably “The Goat Rodeo Sessions” album featuring cellist Yo-Yo Ma, as well as the contemporary “folk noir” trio Sometymes Why; she even guested on a jazz album by the Dave Douglas Quintet. Most of all, she was working in earnest on “Fossils,” which included her composition “Lay My Burden Down” that Alison Krauss had recorded on her Grammy-winning country album. “Fossils” was an experiential compendium of sorts, representing styles from folk to pop to jazz with which O’Donovan had become familiar over the previous decade or more; the album even had its own familial connection – her sister Nuala (a brilliant vocalist herself) sang on the title track.

In fact, “Fossils,” which garnered much critical acclaim, presented a challenge to O’Donovan. “The biggest struggle is your second album, because you don’t want to do the same record twice,” she explained. “I really liked working with my producer Tucker Martine on ‘Fossils,’ so I asked him to come back for the next one. But I wanted a different angle, a different sound.”

O’Donovan describes “In the Magic Hour” as a “scavenger hunt” (that staple of children’s/family recreation): full of motifs, metaphors and connections, some direct, others more oblique, for those who seek them. Birds – seagulls, magpipes, harrier hawks, owls and wrens – appear throughout, especially in “The King of All Birds” and “Magpie,” suggestive of flight and return, among other things an allusion to O’Donovan’s travels (literal and figurative). Beaches, as places for youthful frolics and windows on the natural world, are part of the album’s geography (the album cover is a photo of a seven-year-old O’Donovan on the sands at Clonakilty).

Folk and traditional music references also abound, scattered among lyrics or titles, such as “The King of All Birds” (“The wren, the wren, the king of all birds” – although O’Donovan points out her song is not about wrens per se) and “Not the Leaving” (recalling “It’s not the leaving of Liverpool”). “Donal Óg” dates back centuries but is timeless in its evocation of loss (“Sun, moon and stars from me you’ve taken, and God as well if I’m not mistaken”), and the connection is reinforced toward the end with the excerpt of O’Donovan’s grandfather singing “The West’s Awake” – the stirring paean to Irish nationalism penned by Cork’s own Thomas Davis.

“The nostalgia I feel in a lot of the songs takes on different qualities,” said O’Donovan. “Sometimes it’s haunting, sometimes it’s snarky, and sometimes it’s intense – like in ‘Stanley Park,’ which is about when you’re no finally longer a child, and yet you want to feel like you’re someplace, not always out there on your own; there’s a line about being a baby, about being ‘back in the belly where I came from.’ “

The title track is yet another variation on nostalgia and memory, in which she explicitly refers to her grandfather singing songs “of old Ireland, songs ’bout being young again,” and adds, wistfully, “I wish I was young again.”

“People would hear that and say, ‘What do you mean? You’re still young!’” said O’Donovan. “That’s true, but what I’m saying is everyone can look back from wherever in life we are – even if we’re in a good place – and say, ‘Wouldn’t it be great to be that age again?’”

“Magic Hour” also speaks to the idea that the old, familiar places from childhood can continue to furnish new, fresh revelations, as referenced in the line “the sky’s the kind of blue/that you think you know/but you don’t know.”

“I was over there for a wedding a couple of years ago, and I remember looking up at the sky and realizing, ‘Wow, that is the weirdest shade of blue I’ve ever seen,’” said O’Donovan. “The ‘magic’ is still there, if we let ourselves see it.”

A hallmark of the album is the crew of musicians accompanying O’Donovan, including Chris Thile (with a deft mandolin lead on “Magpie”), guitarist Tim Young, bassists Nate Query and Sam Howard, keyboardist Rob Burger and drummer Steve Nistor, as well as the Brooklyn Rider strings. Sara Watkins and Sarah Jarosz, who perform with O’Donovan as the trio I’m With Her, make an especially lovely contribution on “Hornets”: Their vocal harmonies with O’Donovan achieve an angelic grace, while their instrumental backing (Watkins on fiddle, Jarosz on mandolin) helps give the song – about the fascination of wanderlust – its infectious drive.

The spare, spacious “Jupiter” closes out the album and bring together its recurring themes. There’s the beach motif, for one: The song’s arrangement conveys the experience of standing on the sand at low tide, as Nistor’s distant drums crash in and out underneath O’Donovan’s soaring vocals and strummed acoustic guitar, to the soft accompaniment of Brooklyn Rider. There’s also the tug-of-war between here-and-now with what-lies-ahead, acknowledging a future “blacker than a black hole” but staying locked into the present – “keep your eyes fixed on the road.”

“Earth’s shifting temperatures rise,” begins the third verse, “but I’ll never forget the way your skin tastes in July.”

“When I first wrote ‘Jupiter,’ I messed around with the tempo, tried to give it more of a groove,” O’Donovan said. “But ultimately, I decided it was best served by going slow, letting it find its own pace, and Tucker, Steve and Brooklyn Rider did a wonderful job in coming up with the right accompaniment.”

“It’s been said that our memories change over time, and what seemed important to us then can become less so. For me, instead of looking back and seeing that period of my life diminished in some way, it’s grown in beauty and power,” she said. “Most of all, I’m dumbfounded that every summer we were able to make that trip to Ireland – I think, ‘How did my parents pull that off?’ I feel immense gratitude for having had the opportunity to go to this special place all through my childhood, and for what it gave me.”