The conversions thus brought about often left the beauty and originality that had once been typical of the region by the wayside, which adversely affected the village's appearance.

Besides the single-family houses built haphazardly in the old village core, Reichweiler has a new building zone, begun in 1965, with three phases, named Bruchwasem.

Frequent finds from early La Tène times and the time of the Treveri (a people of mixed Celtic and Germanic stock, from whom the Latin name for the city of Trier, Augusta Treverorum, is also derived) within Schwarzerden's or Reichweiler's limits behind the Mithraic monument, mainly in the shape of urns, human remains and wartime equipment such as sword tips, shield bosses and items for daily needs, even if they are not well preserved, show that the land was settled by more or less sedentary people in those days.

A stone figure depicting the Roman smith god Vulcan can now be found in the Saarländisches Landesmuseum (State Museum) in Saarbrücken.

Further, it should be mentioned that these rich finds have come from both Celtic and Roman times, and that they, along with the Mithraic monument, were originally grouped into the municipality of Schwarzerden, but owing to an arbitrary boundary adjustment, perhaps in the Middle Ages, they have found themselves within Reichweiler.

The ecclesiastical lordships that earned the greatest importance in the Reichweiler area were the Archbishopric of Reims (particularly the Remigiusland) and the Bishopric of Verdun.

Bequeathed to him by the Frankish nobleman Adalgisel Grimo were great landholds around Tholey and the broader area (Sankt Wendel, Baumholder), which were entrusted to the Episcopal Church of Verdun.

This would be the only way to explain how in 1273, Countess Elisabeth of Blieskastel and Bitsch donated the village of Reichweiler (and likewise Bubenhausen, nowadays a constituent community of Zweibrücken) along with its appurtenances to the Wörschweiler Monastery.

It was then that the lord of the court, “Herr Niclassen, Apten zu Werßweiller (Wörschweiler), zu Reichwiller (Reichweiler)” handed down at a session of his court a Weistum (cognate with English wisdom, this was a legal pronouncement issued by men learned in law in the Middle Ages and early modern times).

Thus, on 29 August 1431, “Henichin Wolf von Spanheim vom Grafen Friederich v. Veldentzen” received, among other things, “half the holdings, the inheritance and the people at Richwilr”, only to pledge this landhold back to the monastery only two days later.

Even common (that is, not noble) fiefholders are named, for example the Amtmann from Sankt Wendel Peter Glock (1500), Georg Trompeter (1527) and Urban Zol (1541).

On 29 May 1700, Tholey Abbey acquired certain tithes at Reichweiler from a Lord of Günderode, a Palatinate-Zweibrücken Amtmann who lived at Castle Lichtenberg.

After the Werschweiler Monastery (today known as Wörschweiler) was dissolved, Reichweiler was grouped into the Oberamt of Lichtenberg in the Duchy of Palatinate-Zweibrücken, within which it formed part of the Niederamt or Schultheißenamt of Konken.

Thereafter, Reichweiler belonged to the Mairie (“Mayoralty”) of Bourglichtenberg, the Canton of Coussel (Kusel), the Arrondissement of Birkenfeld and the Department of Sarre.

On 12 January 1814, under the Basel Resolution, the victorious powers established a joint administration under which Reichweiler belonged to the General Government of Middle Rhine (Mittelrhein) and the Department of Saar, whose seat was at Trier, and later Koblenz.

Reichweiler, along with the whole of the area on the Moselle's right bank, was made subject to the Austrian-Bavarian State Administration Commission, whose seat was at Kreuznach, and later Worms.

For a short time (16 June 1815 to 3 November 1815), Reichweiler, among other places, was assigned to the Kingdom of Prussia, but on the condition that an area containing 69,000 souls be ceded from the former Department of Saar to leaders of lesser states.

As part of this state, it passed by sale under the terms of a treaty – the price received by the little loved ruler, Duke Ernst, was 2,100,000 Thaler – on 31 May 1834 (with effect from 22 September 1834) to the Kingdom of Prussia, which made this area into the Sankt Wendel district within the Rhine Province.

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 Saar in 1919.

The following table shows Reichweiler's population statistics since 1830:[9] The following table shows population development over the centuries for Reichweiler (“F” denotes number of families):[10] The village's name, Reichweiler, has the common German placename ending —weiler, which as a standalone word means “hamlet” (originally “homestead”), to which is prefixed a syllable Reich—, believed to have arisen from a personal name, Richo, suggesting that the village arose from a homestead founded by an early Frankish settler named Richo, thus “Richo’s Homestead”.

They were called Gerweiler, which lay at the municipal limits with Oberkirchen and Freisen, and Würzweiler, on whose site now lies a new building area.

In May 1566, a circular came forth from the councillors at Zweibrücken to the state scrivener at Lichtenberg in which the subjects were ordered henceforth to belong to the parish of Pfeffelbach.

The combination of charges in the lower field is meant to represent the sun god's symbol found at the Mithraic monument (Mithrasdenkmal) in the municipality.

[14] The following are listed buildings or sites in Rhineland-Palatinate’s Directory of Cultural Monuments:[15] Still observed among old customs in Reichweiler is the Wannerschdag (in standard German, Wanderstag, or “Hiking Day”).

This is done on Boxing Day (26 December), when young and old alike hike in groups at various compass headings, mostly arriving in a neighbouring village, where they visit an inn to refresh themselves with food and drink.

Here, the mayor then lays down his accounting report, accompanied for a time with a meal of mutton, which is (or was) laid on by the Jagdpächter (a hunter who holds/held hunting rights as a tenancy).

It may make for curious reading that a village councillor named Simon Brill was suspended from school service (this after his predecessor Pastor Pfeil had decided in 1651 that he was tired of school work) because it turned out that he himself could neither read nor write, or that Johann Fischer Barthel had to leave his post in 1663 because the village's elderly inhabitants feared that the children were becoming cleverer than they were.

Among other reasons for this were a teacher's failure to secure a guarantee of freedom from compulsory labour, overdue wages, the need to pay a herdsman's fee, and so on.

The subjects that were taught were religion, reading, writing, spelling, grammar, organ playing, keeping school and silkworm raising.

At 49°33′10″N 7°17′59″E / 49.55278°N 7.29972°E / 49.55278; 7.29972 stands a 137 m-high transmission tower run by Deutsche Telekom AG, which like the nearby one on the Bornberg is a standard design of the type FMT 16.