Field peas (Pisum sativum L.) are an annual season grain legume crop and are cultivated in areas that are too cold for the cultivation of soybeans. Market opportunities for field peas have increased in recent years, and the cost of cultivation is less for peas than for soybeans. The concentration of starch in field peas is less, but crude protein and amino acids are greater than in cereal grains. Therefore, in addition to providing amino acids, field peas also provide energy to swine diets, which is important because energy is the most expensive component in diets. As a consequence, it is important to determine the energy value of field peas. Agronomic practices, growing location, and differences among varieties may impact the nutritional properties of field peas, including energy digestibility. It was also observed that in-vitro energy digestibility of field peas was increased by reducing the particle size. However, there is no information on the effects of reducing particle size on concentrations of digestible energy (DE), metabolizable energy (ME), or net energy (NE) in field peas fed to group-housed pigs. Likewise, the digestibility of energy in field peas grown in the U.S. has not been compared with the digestibility of energy of field peas grown in Canada. Therefore, the objective of this research was to test the hypothesis that the particle size of field peas and the location where field peas were grown may affect the apparent total tract digestibility (ATTD) of gross energy (GE) and concentration of NE in field peas fed to growing pigs.