Pieterlen has an area of 8.35 km² (3.22 sq mi).
 Of this area, 2.58 km² (1.00 sq mi) or 31.0% is used for agricultural purposes, while 3.92 km² (1.51 sq mi) or 47.1% is forested.
  Of the rest of the land, 1.63 km² (0.63 sq mi) or 19.6% is settled (buildings or roads), 0.13 km² (32 acres) or 1.6% is either rivers or lakes and 0.04 km² (9.9 acres) or 0.5% is unproductive land.

Of the built up area, industrial buildings made up 2.5% of the total area while housing and buildings made up 7.8% and transportation infrastructure made up 6.1%.
 Power and water infrastructure as well as other special developed areas made up 1.7% of the area while parks, green belts and sports fields made up 1.4%.
 Out of the forested land, all of the forested land area is covered with heavy forests.
 Of the agricultural land, 25.0% is used for growing crops and  4.9% is pastures, while 1.1% is used for orchards or vine crops.
 All the water in the municipality is flowing water.

The municipality is located between the Jura Mountains and the Büttenberg mountain in the Bernese Seeland.

On 31 December 2009 Amtsbezirk Büren, the municipality's former district, was dissolved.
 On the following day, 1 January 2010, it joined the newly created Verwaltungskreis Biel/Bienne.
Pieterlen has an area of 8.35 km² (3.22 sq mi).  Of this area, 2.58 km² (1.00 sq mi) or 31.0% is used for agricultural purposes, while 3.92 km² (1.51 sq mi) or 47.1% is forested.   Of the rest of the land, 1.63 km² (0.63 sq mi) or 19.6% is settled (buildings or roads), 0.13 km² (32 acres) or 1.6% is either rivers or lakes and 0.04 km² (9.9 acres) or 0.5% is unproductive land.
Of the built up area, industrial buildings made up 2.5% of the total area while housing and buildings made up 7.8% and transportation infrastructure made up 6.1%.  Power and water infrastructure as well as other special developed areas made up 1.7% of the area while parks, green belts and sports fields made up 1.4%.  Out of the forested land, all of the forested land area is covered with heavy forests.  Of the agricultural land, 25.0% is used for growing crops and  4.9% is pastures, while 1.1% is used for orchards or vine crops.  All the water in the municipality is flowing water.
The municipality is located between the Jura Mountains and the Büttenberg mountain in the Bernese Seeland.
On 31 December 2009 Amtsbezirk Büren, the municipality's former district, was dissolved.  On the following day, 1 January 2010, it joined the newly created Verwaltungskreis Biel/Bienne.
Pieterlen