In 's-Hertogenbosch, the Aa is a wide canal that runs straight to the city center. After reaching the city center, the Aa flows along the northern city walls to join the Dommel just west of the Citadel of 's-Hertogenbosch.
Just east of 's-Hertogenbosch, the Aa meets the Maxima Canal. It does not cross the canal, but is led through tubes that run below it.