Although the official address is Lovat Lane, the more notable side faces the street called "Mary at Hill" where there is a huge two-faced clock extending several feet into the street. There is a narrow alleyway alongside, but no right of way.
The plan of St. Mary-at-Hill is roughly square, with a western tower on the street front flanked by a north and south narthex.. Wren spanned the square space by a barrel vault in a Greek-cross plan, with a dome at the centre, supported on four fluted Corinthian columns. Inside there are some original seventeenth century box pews and matching high quality 19th Century replicas by the eminent woodcarver William Gibbs Rogers.
Sir John Betjeman said of the church:
“This is the least spoiled and the most gorgeous interior in the City, all the more exciting by being hidden away among cobbled alleys, paved passages, brick walls, overhung by plane trees…”
In several books on English folklore, or about ceremonies of London, there is mention of the costermonger's festival held here every October. It also goes by the name "Fish Harvest Festival" or "Harvest of the Sea", associated with the fishmarket that was held at Billingsgate. Another notable ceremony is Beating the Bounds, where notables and children process around the boundary of a parish or ward on Ascension Day, carrying slender rods. Originally the children were whipped (not severely) at points along the route. Almost every example died out in the middle of the nineteenth century, but the account books of St.Mary-at-Hill testify to its existence here. Four shillings were paid for the provision of fruit on the day of the "Perambulation" in 1682. In another example at Chelsea the whipped children were given four pence. One rare surviving example of "Beating the Bounds" is at the nearby church "All Hallows by the Tower", where it is held every three years.
Parliament outlawed new burials in the City of London during the Victorian era, forcing the closure of its churchyards; in 1847 the church acquired a small part of the consecrated ground in West Norwood Cemetery for its own parish use.