Following Union, the membership of St Andrew's-with-Castle Gate resolved to retain the former St Andrew's premises on Goldsmith Street, where it still worships and hosts its many other activities, while the Castle Gate premises were acquired by the Congregational Federation (bringing together those Congregational Churches that elected to remain independent on the formation of the URC), for use as its national headquarters.

The history of Castle Gate Congregational Church can be traced to the mid-seventeenth century and the period of the English Civil War.

St Andrew's, in its turn, established the Hyson Green Mission (Noel Street) in 1885, where a new Church was opened in 1901, to survive until the close of WW2.

In October 2022 the church members voted in favour of offering same sex marriage, and shortly thereafter published statements online confirming their commitment to LGBTQ+ inclusion.

The archives of St Andrew's with Castle Gate URC, its precursors, and a number of their daughter churches are now located at The Department of Manuscripts and Special Collections at The University of Nottingham (King's Meadow Campus, Lenton Lane, Nottingham NG7 2NR), where it is accessible to all bona fide enquirers at the discretion of the Keeper of the Manuscripts.