Any county not listed for this state is $37 unless otherwise indicated.

1840 Census
Iowa - $37 each county

1850 Census 
Iowa - $37 each county 

1860 Census
Iowa - $37 each county except for the following:
       $57 each for the counties of Clinton, Crawford, Dallas, Davis,
                  Decatur, Delaware, Des Moines, Dickinson, Iowa, 
                  Jasper, Jefferson, Jones, Kossuth, Lee, Lucas, 
                  Madison, Mahaska, Manona, Marion, Marshall, Polk, 
                  Pottawattamie, Washington, Wayne 
       $97 each for the counties of Clayton, Bubuque, Henry, Jackson,
                  Johnson, Keokuk, Louisa, Linn, Scott, Warren, Wapello

1870 Census
Iowa - $37 each county except for the following:
       $57 each for the counties of: Appanoose, Audubon, Boone, Bremer, 
                  Clarke, Clay, Crawford, Dallas, Davis, Decatur, Des 
                  Moines, Dickinson, Emmet, Fayette, Harrison, Henry, 
                  Jasper, Keokuk, Kossuth, Mills, Mitchell, Monona, Monroe, 
                  Montgomery, Muscatine, O'Brien, Page, Wayne, Webster,
                  Winnebago, Winneshiek  
       $97 each for the counties of: Benton, Black Hawk, Clayton, 
                  Jackson, Jefferson, Johnson, Jones, Linn, 
                  Madison, Mahaska, Marion, Marshall, Pottawattamie, 
                  Scott, Wapello, Warren, Washington 
     $147 each for the counties of: Clinton, Dubuque, Lee 

1880 Census
Iowa - $37 each county except as follows:
       $27 each for the counties of: Bremer, Floyd 
       $47 each for the counties of: Jones, Poweshiek 
       $57 each for the counties of: Benton, Blackhawk, Dubuque, Emmet,
                  Jefferson, Johnson, Lee, Louisa, Linn, Lucas, Lyon, 
                  Madison, Marion, Scott, Story, Tama, Taylor, Union,
                  Van Buren, Wapello
       $97 each for the counties of: Clinton, Fayette, Mahaska, 
                  Marshall, Sac
      $197 each for the counties of: Polk, Pottawattamie
    OR $22 each Enumeration District (EDs) 

1900 Census
Iowa - $37 each county except as follows: 
       $57 each for the counties of Benton, Boone, Brewer, Buena Vista,
                  Buchanan, Butler, Calhoun, Carroll, Cass, Cedar, 
                  Clayton, Crawford, Des Moines, Dickinson, Fayette, 
                  Franklin, Hamilton, Hardin, Harrison, Henry, Iowa,
                  Jackson, Jasper, Jefferson, Johnson, Jones, Keokuk,  
                  Louisa, Madison, Mahaska, Marion, Marshall, Monona,
                  Monroe, Montgomery, Muscatine, Plymouth,
                  Pottawattamie, Shelby, Sioux, Story, Tama, Taylor, 
                  Union, Vanburen, Warren, Webster, Winneshiek, 
                  Woodbury, Worth, Wright  
       $97 each for the counties of: Blackhawk, Clinton, Kossuth, Lee,
                  Linn, Polk, Poweshiek, Scott, Wapello, Winnebago, 
                  Woodbury 
      $197 for the county of Dubuque

1910 Census
Iowa - $37 each county except for the following:
       $57 each for the counties of: Appanoose, Blackhawk, Harrison, 
                  Henry, Jasper, Lee,  Louisa, Lucas, Marion, Mitchell,
                  Montgomery, Muscatine, Plymouth, Poweshiek, Sac, 
                  Story, Tama, Warren, Wapello, Webster, Woodbury, 
                  Worth, Wright 
       $97 each for the counties of: Boone, Clinton, Des Moines, Linn, 
                  Pottawattamie, Scott, Winnebago, Winneshiek, 
                  Woodbury 
      $197 for the county of: Polk 

1920 Census 
Iowa - $37 each county except for the following:
       $57 each for the counties of: Boone, Buchanan, Clinton, Hamilton, 
                 Jasper, Johnson, Lee, Mahaska, Marshall, Wapello, Webster 
       $97 each for the counties of: Black Hawk, Dubuque, 
                 Pottawattamie
      $147 each for the counties of: Linn, Scott
      $247 for the county of: Woodbury
   Polk Cty. & City of Des Moines - $397
   (use "Comments" to get info on reducing cost of populous areas)