In the 47th year of his age.

FAG contributor 46820671 (Denise) has suggested the following information:
Date of birth: June 27, 1759
Place: Wilmington, Middlesex, Massachusetts

In researching this suggestion, I have located the following:

Massachusetts Marriages, 1633-1850: Reuben Buck and Esther Harnden were married in Wilmington, Middlesex, Mass, on 2 May 1782.

1790 United States Federal Census in Wilmington, Middlesex, Mass -
Reuben Buck
1 male under 16
2 male 16 and over
4 female

1800 United States Federal Census in Wilmington, Middlesex, Mass -
Reuben Buck
3 male under 10 (Sewall 10, Joseph 2, Alvah mos.)
1 male 10 through 15 (Reuben 13)
1 male 26 through 44 (Reuben 41)
2 female under 10 (Lydia 7)
1 female 10 through 15 (Molly 15)
1 female 16 through 25 (Esther 17)
1 female 26 through 44 (Esther 37)

In the 47th year of his age.

FAG contributor 46820671 (Denise) has suggested the following information:
Date of birth: June 27, 1759
Place: Wilmington, Middlesex, Massachusetts

In researching this suggestion, I have located the following:

Massachusetts Marriages, 1633-1850: Reuben Buck and Esther Harnden were married in Wilmington, Middlesex, Mass, on 2 May 1782.

1790 United States Federal Census in Wilmington, Middlesex, Mass -
Reuben Buck
1 male under 16
2 male 16 and over
4 female

1800 United States Federal Census in Wilmington, Middlesex, Mass -
Reuben Buck
3 male under 10 (Sewall 10, Joseph 2, Alvah mos.)
1 male 10 through 15 (Reuben 13)
1 male 26 through 44 (Reuben 41)
2 female under 10 (Lydia 7)
1 female 10 through 15 (Molly 15)
1 female 16 through 25 (Esther 17)
1 female 26 through 44 (Esther 37)