Here's what I've got on this William Buchanan. I'm not connected to this line as far as I know. You might check for more with:
Gary O. Green <ggreen@wilmington.net> 6720 Creek Ridge Rd, Wilmington, NC 28411-8908

Descendants of Robert Buchanan
------------------------------
1-Robert Buchanan b: Scotland
+ ?
|--2-Mungo Buchanan b: Scotland, d: 1696
+Barbara Leckie
|--3-Mungo Buchanan b: Edinburgh, Midlothian, Scotland
| +Anna Barclay , m: Bet Jan 21, 1684 and Jan 1686, Edinburgh, Midlothian, Scotland, par: John Barclay and Jean Gordon
| |--4-Archibald Buchanan b: Edinburgh, Midlothian, Scotland
| |--4-Andrew Buchanan b: Edinburgh, Midlothian, Scotland
| |--4-Robert Buchanan b: Edinburgh, Midlothian, Scotland
| |--4-John Buchanan b: Edinburgh, Midlothian, Scotland
| |--4-William Buchanan b: Edinburgh, Midlothian, Scotland
| |--4-Barbara Buchanan b: Edinburgh, Midlothian, Scotland
| |--4-Mungo Buchanan b: Oct 18, 1687, Edinburgh, Midlothian, Scotland, d: Dec 1699, Edinburgh, Midlothian, Scotland
| |--4-James Buchanan b: Mar 19, 1690, Edinburgh, Midlothian, Scotland
| |--4-George Buchanan b: Jul 7, 1698, Edinburgh, Midlothian, Scotland, d: Baltimore, MD
| +Eleanor Rogers d: Baltimore, MD, m: 1727, par: Nicholas Rogers
| |--5-William Buchanan b: Jul 1748, Druid Hill Park, Baltimore, MD
| | +Margaret Hill Dorsey , par: Caleb Dorsey and Priscilla Hill
| | |--6-Eleanor Buchanan
| | |--6-James Buchanan
| | |--6-Rebecca Ridgeley Buchanan
| | |--6-Elizabeth Buchanan
| | |--6-Priscilla Buchanan
| | |--6-Edward Buchanan
| | |--6-William Buchanan
| | |--6-George Buchanan
| | |--6-Mary Buchanan
| | |--6-Frances Buchanan
| | |--6-Peggy Buchanan
| | |--6-Anne Buchanan
| | +Hephzibah Brown b: NJ
| | |--6-Charles Adams Buchanan
| | |--6-Susan Buchanan
| | |--6-William J. Buchanan
| | |--6-James Madison Buchanan
| |--5-Joshua Buchanan, Sr. b: Auchintorlie, Dunbarton, Scotland
| +Nancy
| |--6-James Buchanan
| |--6-John Buchanan b: Montgomery, VA, d: 1834, Pike Co., IL
| | +Mary Russon , par: Joseph Russon and Mary Rosson
| | |--7-Nancy Buchanan b: Montgomery, VA
| | | +William Prest
| | |--7-Henry P. Buchanan b: KY
| | | +Adeline Johnson
| | | +Selma E. Sitton
| | | +Catherine E. Yocum
| | |--7-Shular Buchanan
| | |--7-James E. Buchanan
| | | +Elizabeth Rigsby , m: Jul 13, 1815, Scottsville, Allen Co., KY
| | |--7-Frances Buchanan
| | |--7-Stanley Buchanan b: Allen Co., KY
| | |--7-John R. Buchanan
| | |--7-Sallie Buchanan
| | |--7-Michael Buchanan
| | |--7-Austin Buchanan b: Allen Co., KY
| | | +Sarah W. Roachell
| | | +Lydia Margaret Reynolds
| | |--7-Valentine Armstead Buchanan b: Allen Co., KY, d: Spring Creek Township, Pike Co., IL
| | +Nancy Emoline Hamilton , m: Scott, IN
| |--6-Joshua Buchanan, Jr. b: VA, d: Jul 9, 1854, Big Difficult, Allen Co., KY
| | +Susan Wood , m: May 8, 1802, Warren Co., KY, par: John Wood and Martha Ogle
| |--6-William Buchanan b: 1767
| | +Effie White , m: Jan 1818, Switzerland, IN
| |--6-Thomas Buchanan b: 1769
| +Elizabeth Anderson , m: May 18, 1815, Madison, Jefferson Co., IN
|--3-William Buchanan
|--3-Robert Buchanan
|--3-James Buchanan