Brussels International Airport, or Cologne Airport in Germany, are approximately the same distance from the circuit - 110km and 90km respectively. The closest airport is in Maastricht, but it can be more difficult to get a direct flight. All airports have the usual taxi and bus services but you will probably want to take a train or drive to the towns near the circuit.
If you're travelling between the UK and Europe then Sea France run regular channel crossings.
There are a number of smaller accommodation options close to the circuit in the beautiful town of Spa but these sell-out quickly. More likely you will need to look in Liege, Aachen, or Maastricht. These towns are a reasonable distance from the rural setting of the circuit and so make sure you plan your travel ahead.
Useful information and assistance on accommodation can be obtained from the Belgian Tourist Office at www.belgiumtheplaceto.be
The Spa-Francorchamps circuit is located in the scenic Ardennes forest region. It's worth bring an umbrella because the odd shower is not uncommon. You may want to consider the following for travel to the circuit:
The interactive map below shows the location of Circuit De Spa-Francorchamps. Use the controls to view the circuit as a traditional map or as satellite images, move around, and zoom in and out.