Zayo Group continues to expand via acquisition, this time via an agreement to buy FiberGate, Inc., a provider of dark fiber services in metro Washington, DC. The total value of the all-cash transaction was not revealed.

Alexandria, VA, based FiberGate controls 130,000 fiber miles (which compose 650 route miles) in the metro DC area. Its network also includes 315 on-net buildings and two recently completed expansions to Frederick and Baltimore, MD.

“The DC/Northern Virginia area is a uniquely important geography for government, data centers, and Internet connectivity,” says Dan Caruso, CEO of Zayo Group in explaining the deal. “The combination of AboveNet’s and FiberGate’s networks will create an extensive fiber footprint in this strategic bandwidth corridor.”

Zayo agreed to purchase AboveNet this past March. That deal is expected to close this summer.

The FiberGate transaction, subject to customary approvals, is expected to close by the end of the third quarter of this year.