Just out of interest, Japan is roughly the same size as the UK and has a population density of 903 people per square mile. They are thirty-fifth in the world's list; we are the 49th most densely populated.
Any idea how they cope when we can't? Of course one (the Netherlands) is famed for reclaiming from the sea.
Here's a list;
http://statisticstimes.com/demographics/countries-by-population-density.php
To be fair I have emboldened larger countries as places like Monaco and Singapore skew the list a bit!
Rank; name; Pop; /sq km /sq mile
1 Monaco 38,897 26,105.37 67,612.62 Europe
2 China, Macao SAR 632,418 21,151.10 54,781.13 Asia
3 Singapore 5,791,901 8,274.14 21,429.94 Asia
4 China, Hong Kong SAR 7,428,887 7,075.13 18,324.51 Asia
5 Gibraltar 34,733 3,473.30 8,995.81 Europe
6 Bahrain 1,566,993 2,061.83 5,340.12 Asia
7 Holy See 801 1,820.45 4,714.96 Europe
8 Maldives 444,259 1,480.86 3,835.42 Asia
9 Malta 432,089 1,350.28 3,497.21 Europe
1
0 Bangladesh 166,368,149 1,278.08 3,310.22 Asia
11 Bermuda 61,070 1,221.40 3,163.41 North America
12 Sint Maarten (Dutch part) 40,552 1,192.71 3,089.10 North America
13 Channel Islands 166,083 874.12 2,263.96 Europe
14 State of Palestine 5,052,776 839.33 2,173.86 Asia
15 Mayotte 259,682 692.49 1,793.53 Africa
16 China, Taiwan Province of China 23,694,089 669.14 1,733.05 Asia
17 Barbados 286,388 666.02 1,724.98 North America
18 Mauritius 1,268,315 624.79 1,618.19 Africa
19 Lebanon 6,093,509 595.65 1,542.73 Asia
20 Aruba 105,670 587.06 1,520.47 North America
21 Nauru 11,312 565.60 1,464.90 Oceania
22 San Marino 33,557 559.28 1,448.54 Europe
23 Republic of Korea 51,164,435 526.22 1,362.91 Asia
24 Rwanda 12,501,156 506.74 1,312.44 Africa
25 Netherlands 17,084,459 506.66 1,312.23 Europe
26 India 1,354,051,854 455.42 1,179.53 Asia
27 Comoros 832,347 447.26 1,158.39 Africa
28 Burundi 11,216,450 436.78 1,131.25 Africa
29 Puerto Rico 3,659,007 412.51 1,068.41 North America
30 Haiti 11,112,945 403.23 1,044.35 North America
31 Israel 8,452,841 390.61 1,011.68 Asia
32 Belgium 11,498,519 379.74 983.52 Europe
33 Tuvalu 11,287 376.23 974.44 Oceania
34 Curaçao 161,577 363.91 942.53 North America
35 Martinique 385,065 363.27 940.86 North America
36 Philippines 106,512,074 357.22 925.19 Asia
37 Réunion 883,247 353.30 915.04 Africa
38 Japan 127,185,332 348.88 903.59 Asia
39 Sri Lanka 20,950,041 334.08 865.26 Asia
40 Grenada 108,339 318.64 825.28 North America
41 Viet Nam 96,491,146 311.19 805.98 Asia
42 El Salvador 6,411,558 309.44 801.44 North America
43 Guam 165,718 306.89 794.83 Oceania
44 United States Virgin Islands 104,914 299.75 776.36 North America
45 Marshall Islands 53,167 295.37 765.01 Oceania
46 Saint Lucia 179,667 294.54 762.85 North America
47 Saint Vincent and the Grenadines 110,200 282.56 731.84 North America
48 American Samoa 55,679 278.40 721.04 Oceania
49 United Kingdom 66,573,504 275.18 712.70 Europe