A $2.9 million project to improve waterfront access in the Bronx unearthed a priceless find — more than 100 pieces of Native American artifacts dating back to 200 AD.

Experts are calling the trove of ceramics, pottery, stone tools and other artifacts found in the southeastern section of Pelham Bay Park one of the most important archaeological finds in New York City history.

“The findings are pretty spectacular,” said Amanda Sutphin, director of archaeology for the city’s Landmarks Preservation Commission, who gave The Post an exclusive tour of the tree-lined site overlooking Eastchester Bay.

Tests show the rare artifacts date back to between 200 AD and 1000 AD — centuries before European settlers made contact with Native Americans, she added.

Sutphin was especially impressed with the condition of the ceramics, which she believes were once used for eating and food preparation.

“I’ve never seen anything like it found in New York City before,” she said.

The first of the artifacts were dug up in 2012, but more extensive excavation work and testing done in the past year through last month made it clear to city officials they were sitting on history worthy of additional exploration.

Some of the artifacts were uncovered just two feet below ground, and city officials said early evidence shows the site was likely once a meeting place for Native Americans who would go there to harvest clams and other food.

The findings have now put the Parks Department “in an unusual place to be in,” said Marcha Johnson, a landscape architect with the agency.

The waterfront-access project — which includes removing a deteriorating seawall and adding a walking path, dog run and other amenities — will “eventually” be completed, but the “top priority” now is ensuring the artifacts are protected, she added.

Construction on the project was formally put on hold last month.

The blast from the past may now force the city to redesign the waterfront project to go around the archaeological site, officials said. The city may also attempt to protect the historic area from future development by declaring it a landmark, although no decisions have yet been made.

A Brooklyn College archaeology class will explore the site further for the city as part of a three-week class project in August. All significant artifacts uncovered will be publicly showcased at the city’s Archaeological Repository in Midtown.

To avoid looting, the city has already covered up the dig areas located within a mere acre of 2,772-acre Pelham Bay Park, the largest park in the city.

The Brooklyn College class and other future city-sanctioned digs will have to rely on GPS tracking equipment to find these areas.

The site is not far from where religious rebel Anne Hutchinson and her family were famously killed in 1643 by Siwanoy Native Americans. The English immigrant set up a small colony there in a bid to escape religious persecution.

It’s unknown if the Siwanoy Native Americans who attacked Hutchinson were descendants of the Native Americans whose artifacts the city uncovered, Sutphin said.

“It’s a great question,” she said.