The first Seilo, known as Seilo Bach, was built in 1856 at a cost of £300. (NPRN 6875) The revival three years later brought considerable groth and the first proper chapel was built at a cost of £1,800. The chapel was rebuilt in 1900 for £5000 in the Gothic style of the long-wall entry type. By 1959 Seilo was the largest church in the Presbyterian Church of Wales with 763 members, but the next decade saw a period of decline. By 1997 the chapel had been demolished for roadworks. A new chapel was built on Bangor Road (NPRN 11902).
