Gallagher & Kennedy, an Arizona based business law firm, will merge with Fennemore, one of the nation’s fastest-growing law firms that has a major presence in the Valley, effective Dec. 1 according to a release on Wednesday.

The two firms, which have roots in Phoenix and have longstanding relationships with businesses, industries and communities in Arizona, will operate under the Fennemore name. The firm will have about 300 lawyers and legal professionals in Phoenix, and more than 800 across the country.

“Both Fennemore and Gallagher & Kennedy have played an important role in the growth of Phoenix and Arizona for generations,” said James Goodnow, CEO of Fennemore in a release. “It is rare to have the opportunity to bring together two firms with this much history, this caliber of talent, and such strong client relationships. We know each other, we respect what each firm has built, and we believe we will be even better together.”

“Uniting is a significant opportunity for our clients and our people,” said Kevin O’Malley, managing partner and shareholder of Gallagher & Kennedy in the release. “Gallagher & Kennedy has built its reputation on strong relationships, practical counsel and a deep understanding of our clients and the communities we serve. Joining Fennemore will give our clients access to additional resources and capabilities, while giving two groups of people who know and respect one another the opportunity to work as one team.”