Oxford Networks, which provides the infrastructure for fiber-optic high-speed internet services, is being purchased by Oak Hill Capital Partners.

Oak Hill said in a news release Thursday that after the transaction closes, Oxford Networks will be combined with FirstLight Fiber, another fiber-optics provider in the Northeast that Oak Hill is in the process of purchasing from Riverside Partners.

Novacap and Bank Street Capital Partners, the current owners of Oxford Networks, will continue as minority partners in the combined company, as will Riverside Partners, the companies announced.

Lewiston-based Oxford Networks began as a local phone company more than a century ago. It purchased Bay Ring Communications last year and now has a network that reaches as far south as Boston. The combined Oxford Networks and FirstLight will have a network with more than 4,800 miles of fiber-optic cables and 10 data centers in New York and New England.

Oxford Networks, which employs about 120, operates primarily in Maine, southern New Hampshire and northern Massachusetts. FirstLight’s operating territory covers New Hampshire, Vermont and New York.

“The acquisition of Oxford Networks represents a key next step in the execution of Oak Hill’s vision to create a leading fiber provider in the northeastern U.S.,” said Scott Baker, a partner at Texas-based Oak Hill.

Oak Hill said it expects to complete the transaction during the final three months of the year.

Financial terms were not disclosed.

Oak Hill is an investment firm that traces its roots to Robert M. Bass, a member of a Texas family that grew its fortune through ranching and oil drilling.

Edward D. Murphy can be contacted at 791-6465 or at:

[email protected]