The population density of that country is 685 per square mile.

那个国家的人口密度为每平方英里685人。

《新英汉大辞典》

One of these countries contains less than a square mile of land.

其中一个国家的土地面积不足一平方英里。

youdao

The average population density of the world is 47 persons per square mile.

世界平均人口密度为每平方英里47人。

youdao

Two ranchers with adjacent properties each donated one half square mile to create the town.

BBC: A colourful journey into California��s wild interior

Another New Mexico blaze had grown to about 1 square mile, state forestry officials said.

WSJ: Wildfires Force Evacuations in California

In the hyper-crowded skyscraper districts of Shanghai, densities can approach 125, 000 people per square mile.

WSJ: To Build Creative Cities, the Sky Has Its Limit by Richard Florida