Arenula, or Regola, Regio VII in 1777, a band of blocks along the Tiber running from Parione down to the bridge at the lower edge.
Source: Old map, public domain
Both names for the seventh region, Arenula and Regula, appear in the cartouche at upper right. Blocks stretch in a long band beside the Tiber, with the Area Farnesiana drawn near the middle, and a few small reference numbers, such as 23 and 30, sit in the southern streets.