Tony Pulis' men scored three headers as Peter Ramage, Glenn Murray and Marouane Chamakh were on the scoresheet at the City Stadium in Virginia.
It saw the Premier League outfit finish their tour of the US with two wins and a draw as they prepare for a return to the United Kingdom.
The hosts, in the third tier in the US, settled the better of the two teams without testing Palace goalkeeper Wayne Hennessey.
After a period of pressure, the visitors took the lead in the 35th minute as Jason Puncheon's corner was headed in by Ramage at the back post.
Palace had a goal ruled out for offside just before half-time before another corner led to a goal in the 52nd minute as Murray headed in.
The win was sealed in the 69th minute as Chamakh got on the scoresheet, heading home Barry Bannan's cross.
Palace return to the UK for a clash against Brentford on Saturday, with their Premier League campaign kicking off with a meeting with Arsenal on August 16.
