  Population dynamics in urban and rural areas are different. Understanding
factors that contribute to local population changes has various socioeconomic
and political implications. In the present study, we use population census data
in Japan to examine contributors to the population growth of residential
clusters between years 2005 and 2010. The data set covers the entirety of Japan
and has a high spatial resolution of 500$\times$500$\textrm{m}^2$, enabling us
to examine population dynamics in various parts of the country (urban and
rural) using statistical analysis. We found that, in addition to the area,
population density, and age, the shape of the cluster and the spatial
distribution of inhabitants within the cluster are significantly related to the
population growth rate of a residential cluster. Specifically, the population
tends to grow if the cluster is "round" shaped (given the area) and the
population is concentrate near the center rather than periphery of the cluster.
