The botanical garden is situated on the Gampaha-Minuwangoda main road, approximately 450 m (1,480 ft) away from Gampaha railway station.

The garden consists of a large variety of plants and many of them are from every corner of the tropical world it is expanding over 43 acres (0.17 km2) and situated next to the Attanagalu Oya and surrounded by paddy fields, a man-made green environment and a secondary forest as well laid out with many interesting sections, eye-catching landscaping and many shrubs, bushes and trees.

In 1825 Governor Edward Barnes planted an extensive garden at this location, on the banks of the Kelani River.

Forest Department, Sri Lanka(1887) was responsible for all major plant introductions for economic and environmental development in the Henarathgoda Botanical Garden.

The newest additions to the 149-year-old botanical garden include boat rides at the Attanagalu Oya and a bridge over the river.

The garden hosts an extensive collection of palms, orchids and trees endemic to the country.

Henarathgoda Botanic Garden is situated about 18 miles (29 km) north-west of Colombo and within 1 kilometre (1,100 yd) from the Gampaha Railway Station, and not more than 500 yards (460 m) from the Gampaha-Minuwangoda road.