The transition to Low Diversity began in 2020, with the White population increasing to 77% and further to 83% by 2021, a level maintained in 2022. This shift coincided with a decrease in the Black population from 23% in 2019 to 12% by 2022, and the Hispanic population dropping from 9% in 2019 to 0% in 2021 and 2022.

The demographic shifts appear to correlate with changes in median income. The neighborhood experienced its lowest median income of $36,940 in 2018, during the period of Moderate Diversity. As the community transitioned to Low Diversity with a White Majority, median income rose, peaking at $59,119 in 2021. However, 2022 saw a decline to $43,176, despite maintaining the same racial composition.

The population has remained relatively stable throughout these changes, fluctuating between 96 and 152 residents, suggesting that the demographic shifts likely resulted from existing residents moving out and new residents moving in, rather than significant population growth or decline.

The trend in Castle Grove towards increasing racial homogeneity contrasts with many urban areas across the United States, which have generally been moving towards greater diversity. The increase in median income from 2018 to 2021, followed by a drop in 2022, might reflect broader economic volatility experienced nationwide.

The small population of Castle Grove makes it particularly susceptible to demographic shifts that can be triggered by the decisions of just a few households. This characteristic sets it apart from larger neighborhoods where demographic changes typically occur more gradually.

Castle Grove has transformed from a moderately diverse community to one with low diversity and a strong white majority over the past decade. This shift has been accompanied by notable fluctuations in median income, highlighting the interplay between demographic composition and economic conditions in small communities.