Portmahon, our second Sheffield Church, resulted from a secession of fifty members from Townhead, in 1833. Their separation arose out of a private dispute in the Church, and Mr. Larom charges the blame "to human imperfection, which will sometimes spoil the working of even divine arrangements." The new community first met in a private house, from thence removing to the Assembly Rooms, and afterwards to Eldon Street.
Their first minister was Rev. A. M. Stalker, and under the pastorate of Rev. D. Rees they erected the Portmahon Chapel in 1839. That there was no serious division between the two Churches is evident from the facts that Mr. Larom travelled through the northern Churches on behalf of the debt on the new chapel; and that, in 1839, Portmahon and Townhead united in an evangelistic effort which added a hundred members to the latter Church.
The best known of the Portmahon ministers was Rev. J. E. Giles, a man of considerable eloquence and power, and the author of the hymn "Hast thou said, exalted Jesus ?" During his ministry of fourteen years (1846-60) the cause prospered exceedingly. Among other ministries much blessed to the Church were those of Revs. T. L. Stockley and H. Trotman. In 1905, a work of extension was undertaken in the building of new classrooms, at a cost of £2300, and in the same year Rev. Chas. Deal undertook the pastorate.