Organisers of Alnwick reckon a one-off free-entry offer along with the fine weather prompted tens of thousands of visitors to visit the Northumberland garden.
Alnwick Castle welcomed 16,000 people while 18,000 visited Alnwick Garden.
Alnwick Garden reckoned the equivalent of nearly 2,500 people swung through the gates every hour - or 42 people every minute.
Chief executive Christian Perdrier said: "We wanted to show those working in the public sector how much we appreciate the hard work they do for our communities by treating them to a day of fun and relaxation.
"Many of these families told us they had never visited the castle or garden before. We've started the summer season with a bang."