Crown Castle Inc. is a real estate investment trust and provider of shared communications infrastructure in the United States headquartered in Houston, Texas.

Among its first operational purchases was the transmission sites of the BBC, where Castle and French communications firm TDF Group outbid NTL Incorporated.

On January 12, 2007, Crown Castle completed the acquisition of Global Signal Inc., another U.S. tower operator which was based in Sarasota, Florida.

[20] In 2015, Crown Castle expanded into small cell technology in order to boost the capability and widen the scope of its network.

Prior to that, in 2014, the company acquired the 24/7 Mid-Atlantic Network with over 800 miles of fiber along the East Coast of U.S.[23] Crown Castle International sold off its Australian assets in 2015, removing its international focus and making the company exclusively operational in the United States.

[11][24] On July 19, 2017, Crown Castle signed an agreement to acquire Lightower, a fiber network operator in the northeast U.S., for approximately $7.1 billion.