Suburban encroachment is a growing concern for many National Guard training installations. The Ethan Allen. Firing Range and Camp Johnson, Vermont, are either experiencing or are completely enclosed by urban encroachment. The objective of this study was to analyze the trends of suburban growth within Chittenden County, Vermont, to evaluate growth and explore future training site viability of the Ethan Allen Firing Range and Camp Johnson. This study focused on historical data, recent real estate transactions, population projections, and county plans for growth. Using historical and contemporary data, I developed a predictive model of suburban encroachment on Camp Johnson and the Ethan Allen firing Range facilities by residential and commercial development. This model may assist land managers make decisions and illustrate the viability of these installations as National Guard training sites. This model may also be applied to other installations with similar concerns.