The present building dates to the early Medieval period. In the churchyard lies the grave of the Welsh poet, Sion Phillips, a contemporary of Shakespeare, who lived at nearby Shell Island, he was drowned whilst crossing from Shell Island to Llandanwg in 1620.
The construction of Capel Salem was started in 1826 and completed in 1851, built of stone in the Vernacular style with a long wall entry plan. It has a slate roof and large stones as quoins and lintels. The Chapel interior remains unchanged and the fittings are contemporary with the chapel building. It has box pews with raked seating descending towards the pulpit against the lower end gable, as in other Welsh chapels built c1860. The chapel house is set back from the chapel and there is a graveyard in front. Capel Salem is now Grade II Listed as a good nineteenth century chapel retaining good character and many original features.
The chapel was made famous in a painting from 1908. In the centre is an old Welsh woman walking between pews, a tall black hat on her head, a shawl creeping over her left arm creating a devilish illusion. The blue paisley detail in the crook of her elbow? This was rumoured to be the devil's eye. Her elbow itself? The devil's nose. A fold of material, his mouth, the shawl's fringing, the devil's beard....and even though Salem's English painter, Sydney Curnow Vosper , denied making these effects deliberate, he admitted he'd put a ghostly figure in the chapel window. The painting was subsequently bought by the makers of Sunlight Soap, exhibited in London and featured in their calendar. The same painting now hangs in the Lever Art Gallery in Port Sunlight, Liverpool and is described as a national icon. A copy of the painting hangs in Salem Chapel.