Found the following at http://extra.entisoft.com/L/a/Ladd.HTM

Ladd:

Ladd is the 1,928th most popular last name (surname) in the United
States; frequency is 0.007%; percentile is 51.497
 
Ladd, Arkansas, United States [Place] is in Jefferson County; location
is 34°8'27"N 91°54'32"W 

Ladd, Illinois, United States [Populated Place] is in Bureau County;
location is 41°22'57"N 89°13'8"W 
Ladd, Illinois, United States [Village]; population was 1,283 in 1990;
housing units was 542 in 1990; location is 41°23'N 89°13'W; land area
is 3,377,000 km^2; FIPS code is 40598 
Ladd, Illinois, United States Postal Service Zip Code is 61329

Ladd, Ohio, United States [Place] is in Pike County; location is
38°59'14"N 83°10'51"W; elevation is 103 feet 

Ladd, Oregon, United States [Place] is in Clackamas County; location
is 45°25'0"N 122°40'8"W 

Ladd, Virginia, United States [Place] is in Augusta County; location
is 38°3'21"N 78°57'13"W; elevation is 1,414 feet 

Submitted by Janet Newell, 1998

Not to overlook additional LADD place names found on StreetAtlas USA CD:
LADD RIDGE, OH  at 38º59.36'N  83º10.36'W
LADD POINT, (Grand Isle) VT at 44º46.16'N  73º16.37'W
LADD BAY, (Grand Isle) VT at 44º44.72'N  73º15.61'W
LADD PEAK (12957'), WY at 43º10.52'N  109º42.15'W
LADD MT. (3940'), NV at 36º53.76'N  116º49.33'W
LADD MT. (1338'), NH at 43º34.57'N  71º33.34'W
LADD MARSH GAME MGMT. AREA, OR at 45º15.32'N  118º02.22'W
LADD HILL, OR at 45º16.46'N  122º51.39'W
LADD HILL, ME at 45º17.38'N  69º06.82'W
LADD HILL (630'), IN at 39º08.33'N  87º31.12'W
LADD HILL (506'), CT at 41º28.71  72º14.78'W
LADD'S COVE, TN at 35º10.34N  85º47.80'W
LADDS, TN (Community) at LADD'S POINT, TN at 35º00.50'N  85º32.70'W 
LADD'S CREEK at LIBERTY HILL, AL at 34º50.35'N  85º41.73'W
LADDS (Community), GA at 34º08.92'N  84º49.77'W
LADD CANYON, OR at 45º12.82'N  118º01.39'W
LADD CANYON, NV at 40º14.34'N  117º48.98'W
LADD CANYON, CA at 33º44.89'  117º38.45'W
LADD, AK (Town) at   61º0606'N  151º06.82'W
LADD ARBORETUM in CHICAGO  at 42º03.35'N  87º42.21W
LADD'S CIRCLE (Community or Park in Portland), OR at 45º30.52'N  112º38.95'W
LADDSBURG, PA at  41º34.50'N  76º25.04'W
LADDONIA, MO at 39º14.55'N  91º38.78'W

Submitted by JIM CHRISTIAN 1998