Speaking to potential donors at the event, which was held at the Royal Society in London, Harry said how proud he was to be patron of the organisation and talked of his reaction to seeing a mock earthquake.
"I was struck by their willingness to drop everything at a moment's notice - despite the fact I'd do that in my job anytime - and step into the heart of the crisis no matter where it is in the world, leaving loved ones behind.
"And to do this knowing that very few people will have any idea what contribution they have made," added Harry. "They are extraordinary people and this is an extraordinary organisation."
The Queen's grandson watched as three volunteers demonstrated how they would respond in the aftermath of an earthquake, working from a canvas tent complete and utilising first aid kits, satellite phones and maps.
Dressed in a smart blue suit and a burgundy tie, Harry chatted to the Chairman of Trustees Roy Wood, MapAction's Chief Executive Liz Hughes and their guests.
"We are grateful to Prince Harry for the generosity displayed through his ongoing commitment to MapAction's work," said Liz. "Unique events such as this reception offer the perfect opportunity to attract new donors and further engage long-term support for the organisation's future.
"It also allows us to express our thanks to all those involved with helping reach people in their urgent time of need."