The claim: There are more border crossings in Ireland than on the whole of the EU's eastern border.
Reality Check verdict: This is true - there are 137 land border crossings to the east of the EU, compared with 275 between Northern Ireland and the Republic of Ireland.
Senator Mark Daly, deputy leader of Fianna Fail, was on BBC Radio 4's Today programme on Wednesday, discussing the complexities of the Irish border.
"There are over 300 miles of border between the north and south of Ireland," he said.
"And there are more border crossings on this island than there is between the European Union and all the countries to the east of it."
It is hard to find a precise figure for the number of land border crossings in Ireland, because there is no definitive view of how major a track or path has to be before it counts as a border crossing.
A reasonable figure, though, comes from a website called BorderCrossingMemories.com, which has an interactive map showing the location of 275 crossings.
During the Troubles, only 20 of them were open.
What makes the border particularly tricky is that some roads cross the border several times, especially around Fermanagh.
This is in stark contrast to the eastern border of the EU. On the border between Poland and Ukraine, for example, looking at a map there are only 11 crossings on a 330-mile border and most of them are on major roads.
Information about the EU's eastern border comes from Frontex, the European border and coastguard agency.
It measures the land border as being 6,000km (3,720 miles) long, covering the borders between EU member states and Belarus, Moldova, Ukraine and Russia.
It cannot give a figure for the number of roads crossing that border, but it sent a link to a list of borders in EU states. The list was prepared as part of the establishment of the Schengen passport-check-free zone that runs along much of the eastern border of the EU (although not all - Romania, for example, is an EU member but not part of Schengen).
So the Romanian borders are based on just counting from a map.
Frontex does not consider the borders with Turkey to be part of the eastern border, although if they were counted there are two land borders with Greece and four between Bulgaria and Turkey (those also counted on a map).
So that gives a total figure of 137 land border crossings, about half as many as there are in Ireland, despite being 12 times its length.