The women were arrested yesterday for blocking the road outside Phnom Penh City Hall to protest against flooding in the capital's Boeung Kak neighbourhood.
They are from the few dozen families that have persisted in the area once known for its 320-acre lake until it was filled with sand in 2010 to make way for a private development, displacing thousands who lived in stilt houses on its waters and surrounding banks.
Judge Mong Mony Sophea of Phnom Penh Municipal Court ruled the women were guilty of "creating a public traffic jam", sentencing each to a year in jail and a fine of about $500.
Activists say land conflicts are Cambodia's most pressing human rights issue.
Last month victims of land grabs called on the Hague-based International Criminal Court to probe their mass evictions as a crime against humanity by the state.
Aid groups estimate that 770,000 people, or six per cent of Cambodia's population, have been evicted since 2000, including 20,000 people in the first three months of 2014.
At least 10 million acres of land have been confiscated, which represents 22 per cent of Cambodia's land area, often for lucrative rubber or sugar plantations.
"It is a serious violation of human rights, threatening them against protesting about an important land issue," he told AFP.
According to LICADHO, police arrested three other women and a Buddhist monks today when they protested outside the court to demand the release of the jailed activists.