Situated by Lake Mälaren it is distinguished by its nature. The overwhelming majority of the population are located to one of the three towns Kungsängen (pop. 7,500), Bro (6,200) and Brunna (4,000), and most of the remaining area is taken up by countryside, a substantial part of it being agricultural.
As apparent from its coat of arms, Upplands-Bro takes pride in its pre-historic history, and boasts some of the oldest ancient remains in Sweden. From the Iron Age, about 4,000 burial places have been found, and the remains from the Viking Age include 20 runestones.
Every one of the six parishes also hosts a medieval church, built between 1100-1400.
In the 15th century, the fortress Almarestäket was built in the municipality, just east to the present location of Kungsängen. It was the seat of the Swedish archbishop until the Archbishop Gustav Trolle besieged himself there in 1517, leading to the demolition of the fortress in 1519. The ruins can still be visited.