This is the city's main square, and it is indeed a perfect square, measuring 330 hands (each hand corresponds to 22 cm). The four sides, nowadays adorned with trees and benches, make it a very delightful spot. The square's original name was Praça Real (Royal Square) and then it changed to Praça do Comércio (Trade Square) before being given its current name Praça Marquês de Pombal (Marquis of Pombal Square), in memory of the city's founder.

The geometric urban layout of the Pombaline city is the only example of Enlightenment design in Portugal. All the city's roads converge towards the Praça Marquês de Pombal, which has a central obelisk (a monument which pays tribute to King D. José) and four turrets, which house the Town Council and the Igreja Matriz (Main Church). Along the river front, the historical section of the city is delimited by two more towers, positioned symmetrically in relation to the customs building (Alfândega).  

This wide spacious, perfectly square, each side has precisely 330 feet of 22 cm. The Marquês de Pombal Square is the largest urban impact and the urban element par excellence, after the village of the facade.

The used constructive strategy sought to place the square as close as possible to the Guadiana, lying just two blocks from this. Although not constitute the geometric center of the plant is the civic and commercial center of the village. There were the Town Hall and the chain to the east, the Guard Corps to the south and north to Church. The remaining buildings were intended to trade on the ground floor and housing on the first floor. The four corners of the square are marked by four morphologically similar lumps and center stands the obelisk topped by a crown. Although not the geometric center, the  Plaza is a central nuclear and space by bringing together the public and commercial services.