You didn't give much to work with, so this may very well not be the right people.However there was a Clinton Knowlton with a wife Sarah in the 1900, 1910 and 1920 census in NH.In 1910 and 1920 they were in Grafton County, but in 1900 they were in Belknap County.The 1900 census says Sarah was born in Feb., 1872 and that she and her parents were born in NH.In 1880 there is a Sarah Tilton in the household of Daniel L. Tilton in Sanbornton, Belknap, NH.He is 58 and born in NH. His wife is Laura A., and she is 38, so she may not be his first wife.
This Clinton and Sarah had a son Harold born in May 1900, and in 1910 there is a daughter named Olive (probably) or possibly Alice, while in 1920 there is an Olive, listed as Clinton's mother, age 74.
There's an article in the Register, vol. 67 p. 282 that has what appears to be this Daniel L. Tilton and Laura.It says Laura was Laura A. Pike and that Daniel was the son of Daniel Tilton and Hannah Simpson.The article goes back several generations from Laura Pike who was the daughter of an Ezekiel Pike and Sarah Huckins--the article takes the Huckins line back.
As I said, I have no idea if this is the right couple, and I am obviously making other assumptions.I know nothing about this family except what I just looked up, and have no idea if it's accurate.