Four bodies were discovered on Friday and another three on Saturday in Habarana Forest Reserve.
Authorities said all of those found were females from the same herd, and one had been pregnant at the time.
Wildlife and security officials are continuing to search the area for signs of any more dead elephants.
Preliminary post-mortem examinations began over the weekend. While it is not yet clear what caused their deaths, officials suspect they may have been poisoned by angry villagers for destroying crops.
On Monday, another elephant was found shot dead in Sri Lanka's central reserve, though it is unclear if the deaths are related.
Killing wild elephants is illegal in the country, though elephant populations frequently come into conflict with rural communities.
The expansion of villages and farms has contributed to a loss of habitat and supplies of food and water for the animals.
Dozens of elephants are kept in captivity to raise income from tourists, while others are forced to march at local festivals.
Earlier this month, 17 people were injured at a religious procession in Kotte when two elephants ran amok.
The treatment of these animals was also brought into focus after the death of a 70-year-old elephant, Tikiri, whose emaciated state sparked a public backlash.
The last official census of wild elephant numbers was held in 2011, and revealed 5,879 were left in Sri Lanka - one of the highest population densities in the world. Reuters