It lies in the narrow valley of the Jeckenbach (Rosental) some 320 m above sea level, stretching partly towards the mountain slope on the stream's left bank.

Unterjeckenbach's "twin", Oberjeckenbach, once lay about a kilometre away, but it was swallowed up in 1933 when the troop drilling ground was laid out by the Nazis.

It originally belonged to the Nahegau, and later lay within the jurisdiction of the Hochgericht auf der Heide ("High Court on the Heath"), and aside from the odd period when it was pledged, it was under the lordship of the Waldgraves and Rhinegraves throughout the Middle Ages.

In 1319, it was decided in a legal adjudication that Waldgrave Friedrich von der Kyrburg had claims in the villages around Grumbach, and thus in the two Jeckenbachs, but only a share in the Blutbann (blood court district) and the High Court on the Heath, and no further rightful claims.

Since the establishment of the troop drilling ground by the Nazis in 1933, the village has lain at the end of a short sideroad.

Both Unterjeckenbach and Oberjeckenbach, as well as Hohenroth up on the mountain, were repeatedly burnt down and robbed as Croatian troops of the Imperial Army passed through the area in 1635.

[7] During the time of the French Revolution and the Napoleonic Era that followed, the German lands on the Rhine’s left bank, and thereby Unterjeckenbach too, were annexed by France.

As early as 1793, French Revolutionary troops advanced through the Glan valley and stationed themselves in the villages around Grumbach, including Unterjeckenbach.

As part of this state, it passed by sale in 1834 to the Kingdom of Prussia, which made this area into the Sankt Wendel district.

Later, after the First World War, the Treaty of Versailles stipulated, among other things, that 26 of the Sankt Wendel district's 94 municipalities had to be ceded to the British- and French-occupied Saarland.

[8] Under Rhineland-Palatinate's Landesgesetz über die Auflösung des Gutsbezirks Baumholder und seine kommunale Neugliederung (roughly "State Law For Dissolving the Regional Estate of Baumholder and Annexing It to Municipalities") on 2 November 1993 (GVBl.

S. 518), the former municipal area of the long vanished village of Oberjeckenbach – the Nazis had evacuated it in 1933 for military purposes – was annexed to Unterjeckenbach with effect from 1 January 1994.

Particular names for Unterjeckenbach then also crop up in the historical records, such as Sienjeckenbach (1448, after neighbouring Sien) and Frygechenbach (1448).

This was evacuated after Adolf Hitler came to power in 1933, along with 14 other villages in the region, to make way for the Baumholder troop drilling ground.

Beginning in the late 13th century, the Knights of Saint John held great influence over the Waldgravial-Rhinegravial noble house.

Introduced into the lordship of Grumbach in 1556 was the Reformation, and the Evangelical parish of Herren-Sulzbach was founded, to which Unterjeckenbach has belonged ever since.

The red lion charge is drawn from the arms formerly borne by the Waldgraves, under whose lordship Unterjeckenbach once lay.

Before the troop drilling ground was laid out, Unterjeckenbach's location with regard to transport was considerably more favourable than it is now.

[17] As in the other villages in the Amt of Grumbach, there arose in Unterjeckenbach, as an effect of the Reformation movement towards the end of the 16th century, the first efforts to bring reading and writing to the region's children.