The Khmer Buddhists who make up the vast majority of Cambodians generally cremate their dead and then inter them in stupas at local pagodas. Some keep the ashes in their homes or spread them at a significant spot, but most inter them in stupas.

The most elaborate stupas are reserved for relics or royalty, such as those at Wat Phnom or on Oudong mountain. During the Pchum Benh holiday, Khmer Buddhists travel to the stupas where their ancestors are interred and this may involve traveling across the country if their family came from distant provinces.

While the Khmer usually cremate their dead and inter them in stupas, some ethnic minorities inter their dead in family graves.

This is most common among the Khmer Chinese but I’ve seen family graves behind the homes of other ethnic minorities in Kratie province.

Cambodian Christians often bury their dead in individual graves, not family graves, but since the Church is so young there isn’t a consistent practice yet.