DANBURY — The health network that runs Danbury, Norwalk and New Milford hospitals is joining forces with a four-hospital group in New York to form a $2.4 billion medical system stretching from the Hudson River to the shores of Long Island Sound.

The merger of the Western Connecticut Health Network and Health Quest Systems, which is subject to approval by the states of Connecticut and New York and the Federal Trade Commission, would create a seven-hospital network serving 1.5 million people.

“You have two health networks of similar size coming together in a powerful way to provide more access and capacity for our residents and community members,” said Robert Friedberg, the president and CEO of Health Quest, told Hearst Connecticut Media. “This is a pretty dramatic change, because usually with a deal like this, the health networks are not equals, and you don’t have this sharing of perspective.”

The merger, described as a mutually beneficial deal that brings together 2,600 physicians and 12,000 employees, is designed to strengthen the networks’ position in western Connecticut and the lower Hudson Valley.

“We think that collectively we will be able to bring in services that we currently don’t have, such as neurosurgical procedures that require a high volume in order to attract physicians,” said Dr. John Murphy, president and CEO of Western Connecticut Health Network. “We might be able to bring in pediatric specialties and certain types of cancer treatments.”