Up here, the river was a mere gurgle; a babbling babe finding its way into the world. A few sheep roamed, a kite wheeled and a spring-clean wind ruffled the tussocks on the barren hills and rippled the pools. It was a stark yet striking beginning. As we followed a brand new fingerpost, skirted Llyn Teifi – the river’s official source – and picked up the fledgling flow, there was a sense great things lay ahead, for us both.

The Teifi rises in Ceredigion’s Cambrian Mountains – the untramped “green desert of Wales” – and pours into Cardigan Bay 75 miles (120km) south-west. It’s one of the longest rivers wholly within Wales and, historically, one of its most significant: the beating heart of the country’s fishing and wool-weaving industries, 12th-century abbeys at either end, Wales’s oldest university en route.

However, those abbeys lie in ruin now, salmon and sewin (brown trout) stocks have plummeted, and the mills are shuttered – though the factory in the village of Dre-fach Felindre now operates as the National Wool Museum. Even the future of Lampeter’s venerable university is uncertain following the decision to end undergraduate teaching there. It’s as if the valley has lost its purpose. So some determined local walkers are giving it a new one.

The Teifi Valley Trail, an 83-mile hike following the river from source to sea, officially launched on 25 April, but has been decades in the making. The idea was born back when Ceredigion, Pembrokeshire and Carmarthenshire came under one authority (Dyfed), said Kay Davis of the Teifi Valley Trail Association (TVTA), when we met in Llanybydder. “Then the three counties separated in 1996 and it went off the boil. A long time later, we thought, wouldn’t it be great if there was a trail? So we got together with others in the area and went from there.”

It has been a grassroots, cooperative effort between members of local Ramblers groups, Walkers are Welcome communities and footpath associations along the valley, working to reopen paths, secure permissions, nail up waymarks and create a guide. Thought has been given to route quality, places to stay and accessibility by public transport.

“One of the main reasons for the trail is to get people with backpacks and boots down here to spend money,” added the TVTA’s James Williams. “We’ve seen the economic effect the coastal paths have; we thought we could have a bit of that as well.” Backpacked and booted, my husband and I were here to give it a go.

There’s certainly something powerful about following a river. Walking from Teifi Pools on our first day, that trickle led us across the moor and through wild, wooded valleys or cwms with the exuberance of youth. It soon took us to Strata Florida, the abbey founded in 1164 by Cistercian monks seeking solitude in nature – not to mention access to the area’s abundant timber, pasture, peat, lead ore and, of course, water. Little remains of the abbey now – a grand arch, some fine medieval tiles, a cottage housing a small but fascinating exhibition. But this was once the Westminster Abbey of Wales, second only in fame to St Davids and much larger than the ruins suggest. Many pilgrims made the journey here.

Most have probably never heard of Strata Florida, and the Teifi Valley continued in this vein: a place of secrets and little-heard stories. These ranged from a buried elephant (behind Tregaron’s handsome Y Talbot Hotel, allegedly) to dry-stone walls built by Napoleonic prisoners of war. Llanddewi Brefi village was full of tales. On the old mountain-crossing drovers’ route, it has a soaring Norman church built on a mound said to have been miraculously raised by St David himself. These days, Llanddewi is better known as the scene of an enormous LSD drugs raid in 1977 or as the home of Little Britain’s “only gay in the village”. “Most here didn’t watch the show, and I didn’t mind it,” said Yvonne Edwards, landlady of Llanddewi’s New Inn, a proper no-frills-and-flagstones pub. “It was just annoying, having Australian journalists ringing in the middle of the night, and people stealing road signs.”

Further down the trail, just outside Llanybydder, we found one of Davis’s hidden gems: a woodland path, long unused, that her Ramblers group worked hard to reopen. “It’s tiny,” she’d told us, “but there’s a presence there, a good presence.” Indeed, it was like a shot of Narnia, a short stretch of moss-covered magic.

Over the following days, we flirted with the river. At times we were high above, peering from gorse-covered hill forts, across slopes of sheep-grazed green or through woods flush with bluebells. At others, we were on its banks, once close enough to glimpse an otter raise its silken head in the swirl. Beyond Llechryd, the path squeezed us through a tree-huddled gorge, the river’s murmurings joined by the gossip of thrushes, tits, blackcaps and wrens.

The general mood was soothing. It was hard to imagine this river roisterous with industry, fizzing with fish, busy with boats – Cardigan, within the Teifi’s tidal reach, was once the second-largest port in Wales. It’s a quieter town these days, and looking good, boosted by the restoration of its castle, which was rescued from ruin a decade ago. The castle hosted the first National Eisteddfod in 1176; in celebration of the 850th anniversary, the 2026 festival is being held at nearby Llantwd.

We stayed in one of the castle’s refined rooms, but still had a few miles to go to reach journey’s end. The trail runs via St Dogmael’s Abbey and climbs high for views across the estuary before dropping to meet it at sweeping Poppit Sands. We washed our boots in the shallows, “our” river now indiscernible, swallowed by the sea.

It was a good walk. And perhaps it wasn’t over? “Early on, we had this idea to create the Celtic Circle,” Davis told me: a 175-mile loop linking the Teifi Valley Trail, a section of Wales Coast Path to Borth, and the Spirit of the Miners route from Borth to Strata Florida. “But we’ll see if we still have the energy after this!”

The trip was supported by Discover Ceredigion, Discover Carmarthenshire and Visit Pembrokeshire. For information, downloadable maps and guidebooks, see the Teifi Valley Trail website. Accommodation includes Y Talbot in Tregaron (doubles from £70), the New Inn in Llanddewi Brefi (doubles from £76), the Cross Hands Hotel in Llanybydder (doubles from £108), Emlyn Hotel in Newcastle Emlyn (doubles from £79) and Cardigan Castle (doubles from £110)