When over 240 buildings within the original Helena Historic District were demolished due to urban renewal, the southeastern section where the demolition of the 1970s was the greatest was delisted, and a roughly 5-block area north of the original downtown district was added in 1990.
The residential sections boundaries were not altered at that time, although the construction of Cruse Avenue, a wide, modern street intended to be a traffic bypass, split the residential district from the downtown.
St. Peter's Episcopal Cathedral and the First Unitarian Church (now Grandstreet Theater) were included in this amended district.
The boundary change also resulted in the period of significance being extended from 1900 to 1948 to reflect the significant early 20th century changes to the area.
In addition, the south end of Last Chance Gulch was closed off and a pedestrian walking mall was created.

Historic buildings and areas lost in urban renewal included the razing of 150 buildings in a seven block area and the former Wall street being completely eliminated.
This area was infilled with three modern buildings and a park.
This demolition also resulted in the loss of west State street and what remained of Helena's Chinatown, the Electric Block, Colwell Building the Helena YMCA, the Novelty Block, Homer block, and the most controversial demolition, the Marlow Theater.
When over 240 buildings within the original Helena Historic District were demolished due to urban renewal, the southeastern section where the demolition of the 1970s was the greatest was delisted, and a roughly 5-block area north of the original downtown district was added in 1990. The residential sections boundaries were not altered at that time, although the construction of Cruse Avenue, a wide, modern street intended to be a traffic bypass, split the residential district from the downtown. St. Peter's Episcopal Cathedral and the First Unitarian Church (now Grandstreet Theater) were included in this amended district. The boundary change also resulted in the period of significance being extended from 1900 to 1948 to reflect the significant early 20th century changes to the area. In addition, the south end of Last Chance Gulch was closed off and a pedestrian walking mall was created.
Historic buildings and areas lost in urban renewal included the razing of 150 buildings in a seven block area and the former Wall street being completely eliminated. This area was infilled with three modern buildings and a park. This demolition also resulted in the loss of west State street and what remained of Helena's Chinatown, the Electric Block, Colwell Building the Helena YMCA, the Novelty Block, Homer block, and the most controversial demolition, the Marlow Theater.
Helena Historic District (Helena, Montana)