~~~LEONARD HILLS who died in May 1849 in Hebron, Washington County, NY. Leonard was born abt 1798. His widow was Anna Curtis H. Anna Remarried Asa Gardner On July 4, 1854. LEVI H, JULIA Ann H, CHARLOTTE H, NATHANIEL H, JAMES H, WILLIAM H. H, LORENZO H, ROXY H~~~

You may already have the answer to this since your post is old.
Are you sure it was Hebron? There were only 3 in Hebron, none Leonard on 1840 census. in Hartford, Washington County there is one who is the right age.
In Hebron 1840
George 4 sons, 4 daughters
Jesse too young
Silas too young

Leonard HILLS 1840 Hartford NY, 3 sons, 4 daughters the right age.

NO burials for Hill or HILLS or anything close for the cemetery records i have saved for the Hebron area. If it was indeed Hartford, there are several buried in Granville, adjacent to Hartford. These records were in Margaret Jenks books on cemetery inscriptions.

TAYLOR CEMETERY IN Granville, NY
Levi HILLS buried, a son of Levi, age 9. the stone was too badly worn to read. He was buried among “Taylor” families.
REYNOLDS CEMETERY, S Granville
infant daughter of Nathan [possible the diminutive of Nathaniel] & Amanda d 1852; Willie, son of above, d 1864 age 1; Dea George, son of Nathan, d 1874 age 85 [wife Polly Reynolds]; PH and GH footstones between William Welch and Nathan & Amanda HILLS. MJ’s note – ‘probably Polly [PH] and George [GH] HILLS'
N GRANVILLE CEMETERY
Julia Moriar [1850-1931] and James HILLS [1852-1924];
HILL CEMETERY S GRANVILLE:
David HILLS, d 1834, age 42; 2 infant HILLS daughters, 1 daughter of C&M d 1874, 1 daughter of WR & AM, d 1873. That is all there is. Nearby is buried Sarah HILLS, wife of Matthias B, mother, d 1892, age 66. Eddie HILLS, infant of DL & MC, d 1884; Leslie HILLS, son of DL & MC, 1887-1889; Mary HILLS, wife of Charles E, d 1884; [Following al have surname HILLS or Hill] Frankie, son of Samuel/Mary, d 1867, age 12; Louisa, daughter Samuel/Mary, d 1850 age 3; Samuel [only legible part of stone]; Eunice, wife Samuel, d 1835, age 34; Sybil, widow David, d 1835, age 41; Mary Ann, d 1842, age 25; Huldah, wife Jessie, d 1828, age 51; David S, d 1849, age 27; Samuel J, son Edward/Sarah d 1858, age 2; Sarah Augusta Bump, wife Edward 1831-1904; Sereno M, child of MB & SA, d 1862, age 11; Ida M, daughter MB/SA d 1862 age 7; Eunice O, daughter MB & SA, d 1857 age 9; Theodore W son of MB & SA, d 1862 age 7; Burnham, d 1859 age 74; Thankful, widow Burnham d 1863 age 72; John F, 1846-1918, Pvt Co K, 123 Reg NY Inf; William M, d 1878 age 38 Co K Reg NY Inf; Noah G, d 1902 age 58, Co K 123 Reg NY Inf; Jane Foster, wife George W d 1911 age 87; Noah G, d 1902 age 58, Co K 123 Reg NY Inf,; Ida M, daughter of E&D, d 1857 age 1; Laura, daughter DW&L, d 1852 age 3w; Loami L, son DW&L, d 1857 age 15; Leander, son DW&L, d 1859 age 15; Levi F, son DW&L, d 1865 age 10; David W, d 1868, age 55; Lavinia, d 1898 age 85; Edwards, d 1874, age 48; Asneath, wife Reuben, d 1827 age 43 [this latter stone was at one time found in the Blood St. cemetery in Hartford, which is on the Granville town line. It was not found in 2000]

There are more, but no Leonard. if you want the rest, email me via personal email so I don’t clog the list down any more! if you can't find personal email, it is my user name at comcast dot net