The tallies, carried out by the Washington Post and the Guardian newspapers, are likely to fuel simmering outrage in many US communities that feel police officers are too quick to use deadly force.
America has in recent years been shaken by a series of fatal police shootings that have prompted calls for reforms of law enforcement tactics.
Some of the highest-profile incidents have involved white officers killing unarmed black men or youths, with many of the deaths caught on video camera.
The shootings have galvanised the Black Lives Matter national movement, which has helped raise awareness around the disproportionate rate at which unarmed black men are killed by police.
The FBI's official tally of justifiable homicides in 2014 was 444 (2015 is not yet available.)
The agency's national tally is also incomplete because reporting is voluntary, and not all police departments submit data.
US Attorney-General Loretta Lynch has announced plans to improve data collecting for use-of-force incidents involving police, calling it "vital for transparency and accountability".
According to The Counted, at the Guardian's site, 1130 people had as of Thursday been killed by police last year, - more than three a day, on average.
The Post, which counted only people killed by gunshot, put the number at 979.
The Post found most of those were either armed, had mental troubles, or were fleeing officers who had told them to stop.
In the bulk of cases where officers killed an armed suspect, the individual was white, the newspaper notes, adding that 36 officers were shot and killed in 2015.
However, when it comes to unarmed suspects, black men are disproportionately affected.
The Post found that though black men make up only 6 per cent of the US population, they made up 40 per cent of the cases in which police killed an unarmed man last year.
Yet another high-profile case unfolded last weekend in Chicago, when police fatally shot Bettie Jones, 55, a mother of five, and Quintonio LeGrier, a 19-year-old engineering student.
Both died after police came to a private residence in response to a domestic-violence call.
The city's mayor, Rahm Emanuel, said more police should be armed with Taser stun guns and given additional training.
"There's a difference between whether someone can use a gun and when they should use a gun," Emanuel said, after cutting short his holiday and returning to the city.
The shootings come with Chicago's police already under federal investigation over a video that shows a white police officer, Jason Van Dyke, shooting a black teen 16 times, with most of the gunshots fired as the boy was lying motionless on the ground.
Van Dyke has pleaded not guilty to murder.
The shooting of 17-year old Laquan McDonald, which took place in 2014, has triggered a federal civil-rights probe into the police and calls in some corners for the resignation of Emanuel - a former top White House aide to President Barack Obama.
In the rare cases where police are charged with wrongdoing in shootings, they are often cleared, as they only need to show they felt their lives were in danger at the time of the incident.
Because so many people in America have guns, officers are trained to assume every suspect could be armed.
In a recent study in the Public Library of Science, researchers from Harvard University urged better national counting of police killings.
"Law-enforcement related deaths, of both persons killed by law-enforcement agents and also law-enforcement agents killed in the line of duty, are a public-health concern," the study notes.
