The Waterville Main Street Historic District (Boundary Increase) located in the City of Waterville, Kennebec County, Maine, contains six contributing and four non-contributing buildings and abuts the northern end of the existing Waterville Main Street Historic District. The buildings in the Boundary Increase were not included in the Waterville Main Street Historic District nomination in 2013 because of a lack of historic integrity for six of the ten buildings. The January 2016 removal of 1960s false facades on 155 and 165 Main Street exposed two largely intact historic facades so that six of the ten buildings now contribute to the Boundary Increase area, giving it sufficient integrity for inclusion in the district. The Boundary Increase is significant under National Register Criterion A in the areas of Commerce, and Entertainment and Recreation. As part of the most intact remaining section of the dense historic commercial center in Waterville, the Boundary Increase illustrates the typical pattern of commercial development in first floor retail spaces with office, educational, fraternal, or residential spaces above, and was a part of the hub of the citys entertainment and recreational facilities. The Waterville Main Street Historic District (Boundary Increase) is also significant under National Register Criterion C in the areas of Community Planning and Development and Architecture. The buildings comprise a visually cohesive grouping of commercial and institutional buildings primarily built between 1860 and 1931, which generally retain a high degree of historic integrity. Buildings in the Boundary Increase area are in the Italianate, Colonial Revival, Early 20th Century Commercial, and Art Deco styles. The period of significance for the architecture, 1860 1961, represents the range of built dates for the contributing resources within the Boundary Increase area and extends to the period just prior to major changes undertaken in downtown Waterville as part of an Urban Renewal redevelopment plan which destroyed much of the commercial fabric that historically abutted the district and Boundary Increase area.