The so - called Mud March was his second attempt at a river crossing .
Burnside had been trying to approach the Confederate capital of Richmond , Virginia , by crossing the Rappahannock River at Fredericksburg , but had been soundly defeated .
The so - called Mud March was Burnside 's second attempt at a river crossing .
Burnside had been trying to approach the Confederate capital of Richmond , Virginia , by crossing the Rappahannock River at Fredericksburg , but had been soundly defeated .