Masjid Jummah, on the boundary of Madinah marks the site where the Prophet (ﷺ) led the first Jummah salah, shortly after his Hijrah (migration) from Makkah.
The original mosque erected on the site by the Sahabah was known as Masjid Bani Salim, after the tribe that lived around here. It later became known as Masjid Jummah.