His headstone and WW I draft card have his first name as Louis. Other records have it as Lewis.

1880 United States Federal Census
Name: Lewis D. Barbour
Age: 7
Birth Year: abt 1873
Birthplace: Kentucky
Home in 1880: Saunders, Barren, Kentucky
Race: White
Gender: Male
Relation to Head of House: Son
Marital Status: Single
Father's name: Robbert Barbour
Father's Birthplace: Kentucky
Mother's name: Martha Barbour
Mother's Birthplace: Kentucky
Household Members: Name Age
Robbert Barbour 44
Martha Barbour 42
Matilda F. Barbour 15
Mary G. Barbour 13
James E. Barbour 8
Lewis D. Barbour 7
Lucy L. Barbour 2
Rutha H. Barbour 1m

1900 United States Federal Census
Name: L D Barbour
Age: 27
Birth Date: Apr 1873
Birthplace: Kentucky
Home in 1900: Temple Hill, Barren, Kentucky
Race: White
Gender: Male
Relation to Head of House: Head
Marital Status: Married
Spouse's Name: M F Barbour
Marriage Year: 1896
Years Married: 4
Father's Birthplace: Virginia
Mother's Birthplace: Kentucky
Household Members: Name Age
L D Barbour 27
M F Barbour 23

1910 United States Federal Census
Name: Lewis D Barber
Age in 1910: 37
Birth Year: abt 1873
Birthplace: Kentucky
Home in 1910: Temple Hill, Barren, Kentucky
Race: White
Gender: Male
Relation to Head of House: Head
Marital Status: Married
Spouse's Name: Minnie F Barber
Father's Birthplace: West Virginia
Mother's Birthplace: Kentucky
Household Members: Name Age
Lewis D Barber 37
Minnie F Barber 33 [2 of 4 children living]
Riley R Barber 8
James B Barber 5

U.S., World War I Draft Registration Cards, 1917-1918
Name: Louis Dennis Barber
Race: White
Birth Date: 26 Apr 1873
Residence Date: 1917-1918
Street Address: # 4
Residence Place: Barren County, Kentucky, USA
Physical Build: Medium
Height: Medium
Hair Color: Black
Eye Color: Black
Relative: Minnie Barber

1920 United States Federal Census
Name: Lewis D Barbour
Age: 46
Birth Year: abt 1874
Birthplace: Kentucky
Home in 1920: Temple Hill, Barren, Kentucky
House Number: Farm
Race: White
Gender: Male
Relation to Head of House: Head
Marital Status: Married
Spouse's Name: Minnie F Barbour
Father's Birthplace: Virginia
Mother's Birthplace: Kentucky
Able to Speak English: Yes
Occupation: Farmer
Industry: General farm
Employment Field: Employer
Home Free or Mortgaged: Free
Household Members: Name Age
Lewis D Barbour 46
Minnie F Barbour 42
Riley R Barbour 18
James B Barbour 14
Emma B Barbour 8
Nancy M Piercy 69

1930 United States Federal Census
Name: Dennis Barbour
Birth Year: abt 1873
Gender: Male
Race: White
Birthplace: Kentucky
Marital Status: Married
Relation to Head of House: Head
Home in 1930: Temple, Barren, Kentucky
Dwelling Number: 149
Family Number: 152
Home Owned or Rented: Owned
Radio Set: No
Lives on Farm: Yes
Age at First Marriage: 23
Attended School: No
Able to Read and Write: Yes
Father's Birthplace: Virginia
Mother's Birthplace: Kentucky
Able to Speak English: Yes
Occupation: Farmer
Industry: General Farm
Class of Worker: Working on own account
Employment: Yes
Household Members: Name Age
Dennis Barbour 57
Minnie Barbour 54

1940 United States Federal Census
Name: Lewis D Barbour
Respondent: Yes
Age: 67
Estimated Birth Year: abt 1873
Gender: Male
Race: White
Birthplace: Kentucky
Marital Status: Married
Relation to Head of House: Head
Home in 1940: Barren, Kentucky
Street: Glasgow Hickory College Road
Farm: Yes
Inferred Residence in 1935: Barren, Kentucky
Residence in 1935: Same House
Resident on farm in 1935: Yes
Sheet Number: 11A
Number of Household in Order of Visitation: 206
Occupation: Farmer
House Owned or Rented: Owned
Value of Home or Monthly Rental if Rented: 600
Attended School or College: No
Highest Grade Completed: Elementary school, 5th grade
Hours Worked Week Prior to Census: 41
Class of Worker: Employer
Weeks Worked in 1939: 30
Income: 0
Income Other Sources: Yes
Household Members: Name Age
Lewis D Barbour 67
Minnie Barbour 63

Kentucky, Death Records, 1852-1953
Name: Lewis Dennis Barbour
Death Date: 9 Apr 1950
Death Location: Barren, Kentucky, USA
Age: 76
Gender: Male
Race: White [ancestry.com has it incorrectly transcribed as Black]
Birth Date: 26 Apr 1873
Birth Location: Barren
Father's name: Robert Wm Barbour
Mother's name: Martha Bertram