diagonal: Renato Frick, a pure amateur and now senior player is currently 22-times National Champion of Liechtenstein: http://www.schach.li/xml_1/internet... (the national champion holders are printed in blue).
Frick, still a regular competitor and regional youth trainer, has won all titles between 1976 and 2011, so far.
He is thus surpassing legendary Ortvin Sarapu, the longtime world record holder, having won or co-won the New Zealand championship 20 times (won between 1951/52 and 1990).
However, Carlos Armando Juarez Flores from Guatemala has won his country's championship 25 times (as of 2015, including six titles in a row from 1983-1988 and fifteen in a row from 1993-2007).
Of course, that's one of those records where it is likely to turn up further / new record holders.
Btw.: The longest span between the first National Champion title and the latest or last, belongs possibly to Viktor Korchnoi, impressive 51 years (from 1960 USSR ch up to 2011 SUI ch), are hard to beat.