Observer states to the Danube Commission
| Flag | State | Area, thous.sq.km | Population, mln. inh. (year) | Capital, population, thous. inh. (year) |
 | Kingdom of Belgium | 30,5 | 11,3 (1/1/2017) | Brüssel (Agglomeration) 1 831 (2011) |
 | Hellenic Republic | 132,0 | 10,8 (1/1/2017) | Athens 664 (2011) |
 | Georgia | 69,7 | 3,7 | Tbilisi |
 | Republic of Cyprus | 9,3 | 0,85 (1/1/2017) | Nicosia 276 (2012) |
 | The Republic of North Macedonia | 25,7 | 2,1 (1/1/2017) | Skopje 544 (2015) |
 | Kingdom of the Netherlands | 41,5 | 17,1 (1/1/2017) | Amsterdam 825 (2016) |
 | Republic of Türkiye | 785,3 | 79,8 (1/1/2017) | Ankara 5 270 (2015) |
 | French Republic | 633,1 | 67,0 (1/1/2017) | Paris 2 197 (2015) |
 | Montenegro | 13,8 | 0,6 (1/1/2017) | Podgorica 151 (2011) |
 | Czech Republic | 78,9 | 10,6 (1/1/2017) | Prague 1,28 Mio. (2017) |
Source:
- Data provided by the DC Member States (ST-16);
- EU transport in figures. Statistical pocketbook 2016;
- Wikipedia, the free encyclopedia (ISO 3166-1) and other sources on the internet