  The entanglement entropy between quantum fields inside and outside a black
hole horizon is a promising candidate for the microscopic origin of black hole
entropy. We show that the entanglement entropy may be defined in loop quantum
gravity, and compute its value for spin network states. The entanglement
entropy for an arbitrary region of space is expressed as a sum over punctures
where the spin network intersects the region's boundary. Our result agrees
asymptotically with results previously obtained from the isolated horizon
framework, and we give a justification for this agreement. We conclude by
proposing a new method for studying corrections to the area law and its
implications for quantum corrections to the gravitational action.
