This museum is located within the borders of Ratnapura Municipal Council in Ratnapura-Colombo route. The edifice where the treasure trove is established is the historic Ehelepola manor house. Then it was used as the ancient demesne of District chief and later it has been used as the contemporary national museum building.
This chateau which was the residence of Ehelepola Adigar (chief of a District) who once happened to be the root-course of a major transition in Sri Lankan history is rumored to be the very location where he had done his entire lord of official works after he arrived to Sabaragamuwa from hill country.
This edifice which was splendidly erected in a lock of land about 7.5 acres seemingly has faced several constructions. The large impressive edifice has been used as an official quarters of not less than 50 mayors since 1812 to 1987. It seems that there was a colossal courtyard and a protecting moat surrounding this regal and imperial edifice. Horse-folds, larders and kitchens are in the back space of the complex. Two huge terraces fill the front space of the complex. The gateway was placed to face the kingdom in uplands at northern direction. One of the main doors and the ceiling of the court-houses in the middle are exquisitely decorated with elegant scroll-works. The complex used as an assembly hall seems to be erected in a heaped up land and the remains of the edifice which was referred as a ceremonial terrace can be seen even today.
The existence of two protective tunnels which runs from Ehelepola manor house to the River Kalu that has been established to be secured from antagonistic jeopardy have been proved through excavations done in foundations.
Pre-historic, archaeological, geological, naturalistic, ethnological and anthropomorphic wares in Sabaragamuwa Province have been examined and collected in a private building at Weralupa Village in Ratnapura in 1942 and exhibited to public in 1946. This was the initial phase of Ratnapura National Museum. Then it was moved to a private building adjacent to Ratnapura Main Bus-stand. Ehelepola manor house which is located in center of the town was opted for the National Museum in Ratnapura in 1987 in order to supply a spacious place for the museum since the former place was less spacious. Remarkable relics that are endemic in Ratnapura have been exhibited in this museum including the pre-historic, geological, naturalistic, ethnological and anthropomorphic wares that belong to Sabaragamuwa District.
The pre-historic chamber has been divided into two as anthropic and animal. Fossilized and petrified constituents of Ratnapura fauna which lived in Sri Lanka 120,000-100,000 years back from today and extinct already are exhibited in the chamber of zoology.
The geographical background of Ratnapura 125,000 years back has been recreated in the museum. Pre-historical tools made of animal bones that have been found in Ratnapura gemming mines are also exhibited for display. Attestation of anthropoids belong to Mesolithic age in Asian Continent that have been found from pre-historic places like Bulathsinhala Pahiyangala, Kuruvita Batathota Lena, Kithulgala Belilena, Balangoda Bellan Bandi Pelessa are displayed here. In the geology section, major mineral resources in Sabaragamuwa province like gem, ore iron or pyrites and mica are set up in show. Tools that are adjoined with the pre-historic folk-life in Sabaragamuwa are displayed in anthropic and ethnology section. Thus the great service rendered by the museum in Ehelepola mansion by conserving and exhibiting the historic hereditaments is historically significant and truly appreciable.