The other option before council yesterday was to twin the existing Kinder Morgan pipeline that already runs through the Westsyde neighbourhood, an option that would affect 100 properties.
Councillor Marg Spina said they made the best choice.
"The oil is going to come through anyway, and I'd rather see it come through a twin pipeline through the Lac Du Bois grasslands, rather than already-built Westsyde."
But Peter Wood, with the Canadian Parks and Wilderness Society, says Kamloops shouldn't be forced to choose between a neighbourhood and a park, and there should be a third option.
"We believe that we have the right to question whether we want it at all, and not just to be forced into the lesser of two evils," said Wood.
"People want to count on parks remaining parks, and the idea that you can just change the boundaries to it is really upsetting."
Kinder Morgan has applied to adjust the park boundaries of the Lac Du Bois grassland and three provincial parks for the pipeline project as part of its $5.4 billion expansion of its existing oil pipeline, which runs from Alberta to Burrard Inlet.
The company says all the land will be returned to park status after the proposed pipeline is completed.
The province is collecting public comments on the application until Sunday.
The pipeline company has also presented a similar choice to the City of Burnaby, saying the proposed expansion could either run under a conservation area on Burnaby Mountain or it could twin the existing pipeline running under an established neighbourhood.