It’s a pleasant drive southwest of Chiquimula [1] to the wonderful crater lake of the 1,650-meter-high Ipala Volcano. The summit is most easily accessible from the village of Agua Blanca (you’ll see blue INGUAT signs leading the way), from which a paved road continues to an area near the top. Once at the crater lake, you’ll see a visitors center, where the park rangers collect a modest park fee of $1.50.
A series of nature trails wind their way around the lagoon. You’ll pass a lookout with an excellent view of the 3.5-kilometer-wide lake as well as the entrance to the Cueva de la Leona (Cave of the Lioness). The volcanic crater and its lake were designated as national parks in 1998. Water for four local villages continued to be extracted until very recently, meaning that the lake has lost much of its original water volume. The lake is filled entirely with rainwater.
There are hourly buses and pickups from the village of Ipala, on the north side of the volcano, to Agua Blanca. Minibuses run between Chiquimula and Ipala every half hour. You can camp at the lake or stay in a basic hospedaje in Ipala.
Links:
[1] http://www.moon.com/destinations/guatemala/el-oriente-and-izabal/rio-hondo-esquipulas/chiquimula