diff --git a/src/modules/ekf2/ekf2_main.cpp b/src/modules/ekf2/ekf2_main.cpp
index bae1fcb6bb..4b37e9a61d 100644
--- a/src/modules/ekf2/ekf2_main.cpp
+++ b/src/modules/ekf2/ekf2_main.cpp
@@ -387,6 +387,8 @@ private:
 		(ParamExtInt<px4::params::EKF2_AID_MASK>)
 		_param_ekf2_aid_mask,		///< bitmasked integer that selects which of the GPS and optical flow aiding sources will be used
 		(ParamExtInt<px4::params::EKF2_HGT_MODE>) _param_ekf2_hgt_mode,	///< selects the primary source for height data
+		(ParamExtInt<px4::params::EKF2_TERR_MASK>)
+		_param_ekf2_terr_mask, ///< bitmasked integer that selects which of range finder and optical flow aiding sources will be used for terrain estimation
 		(ParamExtInt<px4::params::EKF2_NOAID_TOUT>)
 		_param_ekf2_noaid_tout,	///< maximum lapsed time from last fusion of measurements that constrain drift before the EKF will report the horizontal nav solution invalid (uSec)
 
@@ -594,6 +596,7 @@ Ekf2::Ekf2(bool replay_mode):
 	_param_ekf2_req_vdrift(_params->req_vdrift),
 	_param_ekf2_aid_mask(_params->fusion_mode),
 	_param_ekf2_hgt_mode(_params->vdist_sensor_type),
+	_param_ekf2_terr_mask(_params->terrain_fusion_mode),
 	_param_ekf2_noaid_tout(_params->valid_timeout_max),
 	_param_ekf2_rng_noise(_params->range_noise),
 	_param_ekf2_rng_sfe(_params->range_noise_scaler),
diff --git a/src/modules/ekf2/ekf2_params.c b/src/modules/ekf2/ekf2_params.c
index c4f256b826..9568ddb6ed 100644
--- a/src/modules/ekf2/ekf2_params.c
+++ b/src/modules/ekf2/ekf2_params.c
@@ -644,6 +644,21 @@ PARAM_DEFINE_INT32(EKF2_AID_MASK, 1);
  */
 PARAM_DEFINE_INT32(EKF2_HGT_MODE, 0);
 
+/**
+ * Integer bitmask controlling fusion sources of the terrain estimator
+ *
+ * Set bits in the following positions to enable:
+ * 0 : Set to true to use range finder data if available
+ * 1 : Set to true to use optical flow data if available
+ *
+ * @group EKF2
+ * @min 0
+ * @max 3
+ * @bit 0 use range finder
+ * @bit 1 use optical flow
+ */
+PARAM_DEFINE_INT32(EKF2_TERR_MASK, 3);
+
 /**
  * Maximum lapsed time from last fusion of measurements that constrain velocity drift before the EKF will report the horizontal nav solution as invalid.
  *