Switchgrass (Panicum virgatum L.) is a native perennial warm season grass (C₄) currently being used as a bioenergy feedstock.   However, little information is available on switchgrass production in the northeastern US.  The objectives of this study were to evaluate the performance of four switchgrass cultivars grown for bioenergy at two locations in New Jersey.  Four switchgrass cultivars (‘Alamo’, ‘Carthage’, ‘Cave-in-Rock’, and ‘Timber’) were planted in a randomized complete block design with three replicates at two locations, Pittstown and Upper Deerfield, NJ in spring of 2007 at a rate of 11.2 kg PLS ha^-1.    Both trials received 60 kg N ha^-1 applied in mid-May of each year.  A single fall harvest was made at each location in 2009 and 2010 for biomass yield.  Percent ash, percent dry matter, and caloric energy value were determined from subsamples of switchgrass plots collected monthly after harvest.  Biomass yields for switchgrass ranged from 8.94 to 13.21 Mg ha^-1.   ‘Timber’ had the highest biomass yields at Upper Deerfield, while no significant difference between cultivars was observed at Pittstown.  Mean ash content decreased after fall harvest at both locations and reached the lowest values in early spring.  Mean ash content ranged from 3.38 to 1.25%.  Mean percent dry matter was lowest at the initial harvest at both locations and continued to increase over time reaching levels where direct harvest without field drying could be accomplished.  Significant differences in energy values were only observed between harvest years at Pittstown, with values ranging from 19.14 to 20.56 J kg^-1.  Results suggest that ‘Timber’, a high yielding, low ash switchgrass variety, could be a promising cultivar for biomass energy production in NJ.