Brooklynn is the elaborated spelling of Brooklyn — from the Dutch Breukelen ("broken land") — the NYC borough founded by Dutch settlers in 1646. A top-200 US baby name since 2009. Brooklynn Andrew — American gymnast. Brooklynn Pumroy — American competitive cheerleader. Sometimes the Brooklynn spelling is associated with the country/Southern naming tradition while Brooklyn is associated with East Coast urban naming.
Brooklynn does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Brooklynn reduce to 9, The Giver. This is a traditional interpretive system, not a factual claim about the name.