Oops, it doesn't look like 'river day' is a national day..

Other days

law

Law Day
cuddle up

Cuddle Up Day
azonto is acceptable

Azonto Is Acceptable Day
slime

Slime Day
bonang

Bonang Day
donate your hair

Donate Your Hair Day
pick me

Pick Me Day
boyfriend

Boyfriend Day
hannah

Hannah Day
artists

Artists Day