William ³ Johnson (Washington²,  James ¹ ) was born circa 1830 in Kentucky.  He married Elizabeth "Betsy"Ann Martin, circa 1848 in Kentucky.  He married Nancy Unknown in Missouri between 1860 and 1870.  He died March 26, 1913 in Douglas County Missouri, buried Old Horton Cemetery, Howell County Missouri.

Children of William Johnson and Betsy Martin are:

My Line        i.         James Washington Johnson, born December 1849 in Kentucky; died
                               March 1928 in Missouri, Douglas County, buried Inman Cemetery.

                    ii.       Sarah Johnson, born circa 1850 in Kentucky.  She married Levi Collins.

                   iii.       Nancy O Johnson, born circa 1855 in Missouri.  She married Ezekiel Collins.

                    iv.      John Wesley Johnson, born circa 1857 in Missouri. He married (1) Nancy Capps ,
                              (2) Martha Chaney.

                    v.       Roanna Johnson, born circa 1858 in Missouri.

Notes for William Johnson:

He is listed in the 1850 Wayne County Kentucky Census:
525/535   William           JOHNS0N    20       M      Laborer       Kentucky
                Elizabeth        JOHNSON    20       F                          Kentucky
                Washington    JOHNSON   9/12*  M                          Kentucky
                                       * Enumerated September 11, 1850

In the 1860 Douglas County Missouri Census he is listed as:
Johnson,  William, 31,  M,  W,  Farmer,  KY,  James, 12,  KY,  Sarah,  8,  KY, Nancy O,  5, MO,  John W, 3,  Roanna,  2, MO.  (He was apparently a widower at that time).

In the 1870 Texas County Missouri, Wood-Richland Township:
William Johnson, 43, KY, Nancy, wife, 47, KY, John W, son, 14, MO, Roena C, dau, 12, MO, Henry, 25, MO.

In the 1880 Douglas County Missouri Census:
JOHNSON      William      M   51    ----       Farming                KY   VA   VA
184/186            Nancy         F    53   wife      Keeping House    KY   NC   PA

In the 1900 Douglas County Missouri Census:
William Johnson, 63,  Widow, KY, VA, VA.  Listed with his son, John Wesley Johnson.

He is listed in the 1910 Douglas County MO Census as  Wm Johnson, 81, Wd, KY, KY, VA, shown as father-in-law living in the household of Levi Collins and wife, Sarah.

Williams appears to have married Nancy Unknown, between 1860 when William was listed  with no wife and 1870 when Nancy is listed as his wife.