Virginia Lieutenant Governor Alexander Spotswood encouraged immigration by advertising in Germany for miners to move to Virginia and establish a mining industry in the colony. Governor Spotswood "planted" 40 settlers on the Rapidan River establishing the colony of Germanna in 1714. These were immigrants from Germany's Sieg Valley, near modern-day Bonn. He told the officials in London that the settlement was intended to fortify the frontier, but in reality, Spotswood expected to get cheap labor to develop a speculative iron deposit. Germanna was the seat of Spotsylvania County from 1720 to 1732. 
Spotswood erected a palatial home and, after the Germans moved away, continued the ironworks with slave labor. Many Germanna families later migrated southward and westward from Piedmont Virginia. 

1714 Colonists from the Siegerland:
Johann Jost Albrecht, Melchior Brombach and wife Maria Elisabetha Fischbach (daughter of Philip and Elizabeth), Jost Cuntse/Koontz and wife Anna Gertrud Reinschmidt, Philip Fischbach/Fishback and wife Elizabeth Heimbach (parents of Maria Elisabetha and Anna Elisabeth), the Rev. Johann Heinrich Hager and wife Anna Catharina Friesenhagen, Peter/Dieter Heide/Hitt and wife Elisabeth Otterbach, Johannes Hoffman, Hans Jacob Holtzklau/ Holtzclaw and wife Anna Margaretha Otterbach, Johnannes Kemper/Camper, Johann Jost Merdten/Martin, Hermann Otterbach/Utterback and wife Elisabeth Heimbach, Johann Jacob Richter/Rector and wife Anna Elisabeth Fischbach (daughter of Philip and Elizabeth), Johannes Spielmann, Johann Heinrich Weber/Weaver and wife Anna Margarethe Huttman.(1)

‘The Germans live very miserably. [T]he town...is pallisaded with stakes stuck in the ground, and laid close the one to the other, of substance to bear out a musket shot. There is but nine families and they have nine houses built all in a line, and before every house about 20 feet from the house they have small sheds built for their hogs and hens, so that the hog stys and houses make a street. This place that is paled in is a pentagon, very regularly laid out, and in the very centre there is a blockhouse made with five sides which answers to the five sides of pales or great inclosure. There is loop holes through it, from which you may see all the inside of the inclosure.’
This was intended for a retreat for the people in case they were not able to defend the palisades if attacked by the Indians. They make use of this Blockhouse for divine service. They go to prayers constantly once a day and have two sermons a Sunday. We went to hear them perform their service, which was done in their own language.(2)

(1) http://germanna.org/things-to-do/research-your-germanna-roots/, wikipedia.com
(2)   Alexander, Edward Porter (editor), The Journal of John Fontaine, and Irish Huguenot Son in Spain and Virginia 1710-1719, The Colonial Williamsburg Foundation, 1972, p.77, virginiaplaces.com

sources of pictures: 
-Fort Germanna, 1714, Germanna Foundation, germanna.org
-German Virginia, 1710-1719, Peter Jefferson's 1747 map of the Fairfax Grant included Germanna and the Tubal Furnace
Source: University of North Carolina, "Early Maps of the American South," A Map of the northern neck in Virginia (by Peter Jefferson, Robert Brooke, Benjamin Winslow, Thomas Lewis, 1747), virginiaplaces.org
-Fairfax Grant including Germanna, 1747, Germanna was located on the southern side of the Rapidan River, outside the area claimed by Lord Fairfax, Source: Library of Congress, A new map of the western parts of Virginia, Pennsylvania, Maryland, and North Carolina (Thomas Hutchins, 1778), virginiaplaces.com