Chemical Bank agreed to acquire Horizon Bancorp.

New York-based Chemical, the nation’s sixth-largest bank, said the merger would take place when New Jersey banking laws permit. Under terms of the agreement, the first between major New York and New Jersey bank holding companies, Horizon’s shareholders will receive about $465 million in cash. The merger, which is subject to approval by regulators and Horizon shareholders, is not expected before Jan. 1, 1989, the companies said. Horizon, the fifth-largest bank holding company in New Jersey, has $3 billion in assets, while Chemical has assets of about $58 billion.