Are you looking at single country pairings for the border size? The closest comparison, both in border length and economic gap is EU/non-EU, when you look at t

Are you looking at single country pairings for the border size? The closest comparison, both in border length and economic gap is EU/non-EU, when you look at the size of the border along the Mediterranean and the Balkans. Another close comparison is South Africa, 4,862 km border (compared to US-Mexico at 3,145 km). Huge economic gap and even larger migration numbers.