Just to build on what Scott wrote above:
Each of these churches has different historical roots.
Free Reformed -- Great Reformation, Secession of 1834
Heritage Reformed -- Great Reformation, Secession of 1834, assorted subsequent secessions in the Netherlands and US.
United Reformed -- Great Reformation, Secession of 1834, and to a lesser degree the Doleantie of 1886, and Union of 1892, and at least two secessions in the US (producing the CRC and later the URC).
As an aside, there's also a difference between URC folks in Canada and the US. As indicated by Scott, a lot of the Dutch-background URC folks in the US are descended from waves of Dutch immigration in the 19th century. Like in the CanRC, most of the Canadian URC people are descended from a wave of Dutch immigration after the Second World War -- which is perhaps why the CanRC and Canadian URC churches tend to be finding common ground more quickly.
Wes Bredenhof, Th.D.
Pastor, Free Reformed Church
Launceston, Tasmania, Australia
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