Orthez straddles the westward-flowing Gave de Pau, with most of the town proper having developed on the right bank.

Several residential developments and an industrial park are located on the left bank, in addition to Sainte-Suzanne, an associated village entity within the town.

An envoy sent in 1569 by Charles IX to revive the Catholic faith had to stand a siege in the battle of Orthez; the city was eventually taken by assault by the Protestant/Huguenot captain, Gabriel, count of Montgomery.

In 1684 Nicholas Foucault, intendant under Louis XIV, was more successful, as the inhabitants, ostensibly at least, renounced Protestantism.

The Gave de Pau is crossed in Orthez by a 14th-century bridge, which has four arches and is surmounted at its centre by a tower.

The most notable building is the Tour Moncade (43°29′31″N 0°46′13″W / 43.49194°N 0.77028°W / 43.49194; -0.77028), a pentagonal tower of the 13th century, once the keep of a castle of the viscounts of Béarn, and now used as a meteorological observatory.