Developed by the Henderson Development Limited, Union Hospital was established in the year 1994. It is the first private general hospital in the Eastern New Territories.

The Hospital project is divided into two phases. Phase one was completed in 1994, includes a 7-storey main hospital building with 4 ward floors which accommodate 200 beds, a 3-storey Medical Centre, a 24-storey staff quarters as well as an underground carpark with more than 170 spaces.

A total gross floor area of 27,756 sq. m. has been constructed and over four hundred million Hong Kong dollars have been expended.

The phase two hospital extension project was completed in 2006. The construction cost HK$210 million. By constructing 4 new floors atop the existing building, an extra 107 beds and more new facilities are provided to cope with the growing demand for the hospital services. The additions include the Minimally Invasive Centre, Day Therapy Centre, Surgical Ward and the 5-star-hotel-like Private Ward.