In the Federal Census of 1850, Sylvester & Abbey, ages 45 & 46, are living at Lockport, Niagara Co., NY. They have 10 (presumed) children in the household: Edwin 21, Emelin 20, Vincy 17, Benjamin 16, Daniel 14, Sarah 12, Charles 10, Elizabeth 8, Henry 6, & George 5. All were born in NY.
In 1860 the Flagler family is still at Lockport, but Abigail appears to be a widow.
Also living in the same town in 1850 is Abby's brother Sherman Remington and his family.
Source note: It was brought to my attention by Ann Bowler (with info from Judith Rae Remington) that Abby and her husband Sylvester were living in Lockport in 1850.