The release follows a meeting with the Hanoi police chief, who promised not to prosecute the villagers and to order a re-examination of local land use.
In 2015 the land in question was allocated to a firm run by the Vietnamese military.
Residents opposed the move, saying they had received inadequate compensation.
Last Saturday, local residents of Dong Tam Commune, a village outside Hanoi, took 38 people captive in protest.
The hostages included police officers and local officials. Some were released earlier this week.
The remaining 19 people were freed on Saturday after a Hanoi official, Nguyen Duc Chung, promised to launch an investigation which is due to conclude in 45 days.
During the dispute, the villagers built barricades and blocked roads to keep police out and the situation intensified.
Local authorities earlier fled the village, leaving residents in control.
The land under dispute covers an area of 50 hectares (124 acres) that the defence ministry allocated to the military-run communications firm Viettel Group in 2015.
Local authorities said that the land had been set aside for a defence project.
However, tensions began to rise when Viettel started clearing the land ahead of construction, with residents attempting to obstruct its efforts.
Disputes over land rights are common in Vietnam because the government does not recognise private land ownership.
Government agencies reserve the right to seize farmland for construction and investment projects. But it is rare for protesters to seize such a large number of officials.
Residents of a village in Vietnam have freed the remaining 19 hostages they were holding in a week-long stand-off over land rights.