From Monticello:

The Thomas Jefferson Foundation has sought to preserve the rural character of this landscape and of the entrance corridors leading to Monticello. Because of this, visitors have the opportunity to view a landscape largely as Jefferson saw it. Protection of the views is an economic issue as well as a preservation issue.

Albemarle County has acknowledged in its Comprehensive Plan Monticello’s value as an historic resource and the importance of protecting its landscape, and views. Monticello and Albemarle County are working to improve the process for those who are developing or building on lands within view of Monticello so that developers are aware of the historic values before they begin the design process. To ensure that property owners and developers have the best information available to assist them when designing new projects or when improving their properties, Monticello has developed a set of voluntary guidelines with design considerations that can that help mitigate visual impacts to Monticello.

Link to voluntary development guidelines: https://www.monticello.org/thomas-jefferson-foundation/preserving-monticello-s-viewshed/

Source of viewshed: http://gisweb.albemarle.org/GISWeb/Welcome.aspx