diff --git a/index.css b/index.css
index 58e92533..12f94071 100644
--- a/index.css
+++ b/index.css
@@ -1438,7 +1438,9 @@ div.states .icon-trash-empty,
 div.states .icon-eye,
 div.states .icon-pin,
 div.states .icon-flag-empty,
-div.states .icon-cw {
+div.states .icon-cw,
+div.states .icon-lock,
+div.states .icon-lock-open {
   cursor: pointer;
 }
 
diff --git a/index.html b/index.html
index 621428ac..d17f7072 100644
--- a/index.html
+++ b/index.html
@@ -2017,11 +2017,11 @@
             </button>
             <button
               id="regenerateStates"
-              data-tip="Click to select new capitals and regenerate states. Emblems and military forces will be regenerated as well, burgs will remain as they are"
+              data-tip="Click to select new capitals and regenerate unlocked states. Emblems and military forces will be regenerated as well, burgs will remain as they are"
             >
               States
             </button>
-            <button id="regenerateProvinces" data-tip="Click to regenerate provinces. States will remain as they are">
+            <button id="regenerateProvinces" data-tip="Click to regenerate unlocked provinces. States will remain as they are">
               Provinces
             </button>
             <button
@@ -2031,8 +2031,8 @@
               Burgs
             </button>
             <button id="regenerateEmblems" data-tip="Click to regenerate all emblems">Emblems</button>
-            <button id="regenerateReligions" data-tip="Click to regenerate religions">Religions</button>
-            <button id="regenerateCultures" data-tip="Click to regenerate cultures">Cultures</button>
+            <button id="regenerateReligions" data-tip="Click to regenerate unlocked religions">Religions</button>
+            <button id="regenerateCultures" data-tip="Click to regenerate unlocked cultures">Cultures</button>
             <button
               id="regenerateMilitary"
               data-tip="Click to recalculate military forces based on current military options"
@@ -2040,7 +2040,7 @@
               Military
             </button>
             <button id="regenerateIce" data-tip="Click to icebergs and glaciers">Ice</button>
-            <button id="regenerateMarkers" data-tip="Click to regenerate markers">
+            <button id="regenerateMarkers" data-tip="Click to regenerate unlocked markers">
               Markers <i id="configRegenerateMarkers" class="icon-cog" data-tip="Click to set number multiplier"></i>
             </button>
             <button
diff --git a/modules/cultures-generator.js b/modules/cultures-generator.js
index 8a804210..94c5f99b 100644
--- a/modules/cultures-generator.js
+++ b/modules/cultures-generator.js
@@ -6,6 +6,12 @@ window.Cultures = (function () {
   const generate = function () {
     TIME && console.time("generateCultures");
     cells = pack.cells;
+    const prevCultures = {};
+    if (cells.culture) {
+      cells.culture.forEach(function (cultureId, index) {
+        prevCultures[index] = cultureId;
+      })
+    }
     cells.culture = new Uint16Array(cells.i.length); // cell cultures
     let count = Math.min(+culturesInput.value, +culturesSet.selectedOptions[0].dataset.max);
 
@@ -51,7 +57,29 @@ window.Cultures = (function () {
     const emblemShape = document.getElementById("emblemShape").value;
 
     const codes = [];
+    let unoccupied = [...populated];
     cultures.forEach(function (c, i) {
+      if (c.lock) {
+        centers.add(c.center);
+        cells.culture[c.center] = i + 1;
+        codes.push(c.code);
+
+        const cultureCells = [];
+        Object.entries(prevCultures).forEach(function ([index, cultureId]) {
+          if (cultureId === c.i) {
+            cells.culture[index] = i + 1;
+            cultureCells.push(parseInt(index));
+          }
+        });
+
+        unoccupied = unoccupied.filter(function (cell) {
+          return !cultureCells.includes(cell);
+        });
+
+        c.i = i + 1;
+        return;
+      }
+
       const cell = (c.center = placeCenter(c.sort ? c.sort : i => cells.s[i]));
       centers.add(cells.p[cell]);
       c.i = i + 1;
@@ -70,12 +98,16 @@ window.Cultures = (function () {
     function placeCenter(v) {
       let c,
         spacing = (graphWidth + graphHeight) / 2 / count;
-      const sorted = [...populated].sort((a, b) => v(b) - v(a)),
+      // Only use cells where there are no culture already on that cell, which may happen if a locked culture
+      // was restored. We can be sure that locked cultures will always be first in the list.
+      const sorted = [...unoccupied].sort((a, b) => v(b) - v(a)),
         max = Math.floor(sorted.length / 2);
       do {
         c = sorted[biased(0, max, 5)];
         spacing *= 0.9;
-      } while (centers.find(cells.p[c][0], cells.p[c][1], spacing) !== undefined);
+      } while (
+        centers.find(cells.p[c][0], cells.p[c][1], spacing) !== undefined
+      );
       return c;
     }
 
@@ -98,6 +130,12 @@ window.Cultures = (function () {
       const count = Math.min(c, def.length);
       const cultures = [];
 
+      if (pack.cultures) {
+        pack.cultures.forEach(function (culture) {
+          if (culture.lock) cultures.push(culture);
+        });
+      }
+
       for (let culture, rnd, i = 0; cultures.length < count && i < 200; i++) {
         do {
           rnd = rand(def.length - 1);
@@ -481,12 +519,17 @@ window.Cultures = (function () {
 
     const queue = new PriorityQueue({comparator: (a, b) => a.p - b.p});
     pack.cultures.forEach(function (c) {
-      if (!c.i || c.removed) return;
+      if (!c.i || c.removed || c.lock) return;
       queue.queue({e: c.center, p: 0, c: c.i});
     });
 
     const neutral = (cells.i.length / 5000) * 3000 * neutralInput.value; // limit cost for culture growth
     const cost = [];
+    const cellsCost = {};
+    cells.culture.forEach(function (cultureId, index) {
+      // Make the cost of cells with an existing culture so high, they won't get picked
+      cellsCost[index] = cultureId > 0 ? neutral : 0;
+    });
     while (queue.length) {
       const next = queue.dequeue(),
         n = next.e,
@@ -494,6 +537,7 @@ window.Cultures = (function () {
         c = next.c;
       const type = pack.cultures[c].type;
       cells.c[n].forEach(function (e) {
+        const cellCost = cellsCost[e];
         const biome = cells.biome[e];
         const biomeCost = getBiomeCost(c, biome, type);
         const biomeChangeCost = biome === cells.biome[n] ? 0 : 20; // penalty on biome change
@@ -501,7 +545,7 @@ window.Cultures = (function () {
         const riverCost = getRiverCost(cells.r[e], e, type);
         const typeCost = getTypeCost(cells.t[e], type);
         const totalCost =
-          p + (biomeCost + biomeChangeCost + heightCost + riverCost + typeCost) / pack.cultures[c].expansionism;
+          p + cellCost + (biomeCost + biomeChangeCost + heightCost + riverCost + typeCost) / pack.cultures[c].expansionism;
 
         if (totalCost > neutral) return;
 
diff --git a/modules/dynamic/editors/cultures-editor.js b/modules/dynamic/editors/cultures-editor.js
index 393967bc..1a71b576 100644
--- a/modules/dynamic/editors/cultures-editor.js
+++ b/modules/dynamic/editors/cultures-editor.js
@@ -228,6 +228,7 @@ function culturesEditorAddLines() {
           style="width: 5em">${si(population)}</div>
         <span data-tip="Click to re-generate names for burgs with this culture assigned" class="icon-arrows-cw hide"></span>
         ${getShapeOptions(selectShape, c.shield)}
+        <span data-tip="Lock culture" class="icon-lock${c.lock ? '' : '-open'} hide"></span>
         <span data-tip="Remove culture" class="icon-trash-empty hide"></span>
       </div>`;
   }
@@ -257,6 +258,8 @@ function culturesEditorAddLines() {
   $body.querySelectorAll("div > div.culturePopulation").forEach($el => $el.on("click", changePopulation));
   $body.querySelectorAll("div > span.icon-arrows-cw").forEach($el => $el.on("click", cultureRegenerateBurgs));
   $body.querySelectorAll("div > span.icon-trash-empty").forEach($el => $el.on("click", cultureRemovePrompt));
+  $body.querySelectorAll("div > span.icon-lock").forEach($el => $el.on("click", updateLockStatus));
+  $body.querySelectorAll("div > span.icon-lock-open").forEach($el => $el.on("click", updateLockStatus));
 
   const $culturesHeader = byId("culturesHeader");
   $culturesHeader.querySelector("div[data-sortby='emblems']").style.display = selectShape ? "inline-block" : "none";
@@ -928,3 +931,21 @@ async function uploadCulturesData() {
   drawCultures();
   refreshCulturesEditor();
 }
+
+function updateLockStatus() {
+  if (customization) return;
+
+  const cultureId = +this.parentNode.dataset.id;
+  const classList = this.classList;
+  const c = pack.cultures[cultureId];
+  c.lock = !c.lock;
+
+  if (c.lock) {
+    classList.remove("icon-lock-open");
+    classList.add("icon-lock");
+  }
+  else {
+    classList.remove("icon-lock");
+    classList.add("icon-lock-open");
+  }
+}
diff --git a/modules/dynamic/editors/religions-editor.js b/modules/dynamic/editors/religions-editor.js
index a76aec30..81933582 100644
--- a/modules/dynamic/editors/religions-editor.js
+++ b/modules/dynamic/editors/religions-editor.js
@@ -212,6 +212,7 @@ function religionsEditorAddLines() {
       <div data-tip="Religion area" class="religionArea hide" style="width: 5em">${si(area) + unit}</div>
       <span data-tip="${populationTip}" class="icon-male hide"></span>
       <div data-tip="${populationTip}" class="religionPopulation hide pointer">${si(population)}</div>
+      <span data-tip="Lock religion" class="icon-lock${r.lock ? '' : '-open'} hide"></span>
       <span data-tip="Remove religion" class="icon-trash-empty hide"></span>
     </div>`;
   }
@@ -242,6 +243,8 @@ function religionsEditorAddLines() {
   $body.querySelectorAll("div > span.icon-arrows-cw").forEach(el => el.on("click", regenerateDeity));
   $body.querySelectorAll("div > div.religionPopulation").forEach(el => el.on("click", changePopulation));
   $body.querySelectorAll("div > span.icon-trash-empty").forEach(el => el.on("click", religionRemovePrompt));
+  $body.querySelectorAll("div > span.icon-lock").forEach($el => $el.on("click", updateLockStatus));
+  $body.querySelectorAll("div > span.icon-lock-open").forEach($el => $el.on("click", updateLockStatus));
 
   if ($body.dataset.type === "percentage") {
     $body.dataset.type = "absolute";
@@ -755,3 +758,21 @@ function closeReligionsEditor() {
   exitReligionsManualAssignment("close");
   exitAddReligionMode();
 }
+
+function updateLockStatus() {
+  if (customization) return;
+
+  const religionId = +this.parentNode.dataset.id;
+  const classList = this.classList;
+  const r = pack.religions[religionId];
+  r.lock = !r.lock;
+
+  if (r.lock) {
+    classList.remove("icon-lock-open");
+    classList.add("icon-lock");
+  }
+  else {
+    classList.remove("icon-lock");
+    classList.add("icon-lock-open");
+  }
+}
diff --git a/modules/dynamic/editors/states-editor.js b/modules/dynamic/editors/states-editor.js
index b16246fd..f6d9be1c 100644
--- a/modules/dynamic/editors/states-editor.js
+++ b/modules/dynamic/editors/states-editor.js
@@ -153,6 +153,7 @@ function addListeners() {
     else if (classList.contains("statePopulation")) changePopulation(stateId);
     else if (classList.contains("icon-pin")) toggleFog(stateId, classList);
     else if (classList.contains("icon-trash-empty")) stateRemovePrompt(stateId);
+    else if (classList.contains("icon-lock") || classList.contains("icon-lock-open")) updateLockStatus(stateId, classList);
   });
 
   $body.on("input", function (ev) {
@@ -288,6 +289,7 @@ function statesEditorAddLines() {
       <span data-tip="Cells count" class="icon-check-empty ${hidden} show hide"></span>
       <div data-tip="Cells count" class="stateCells ${hidden} show hide">${s.cells}</div>
       <span data-tip="Toggle state focus" class="icon-pin ${focused ? "" : " inactive"} hide"></span>
+      <span data-tip="Lock the state" class="icon-lock${s.lock ? '' : '-open'} hide"></span>
       <span data-tip="Remove the state" class="icon-trash-empty hide"></span>
     </div>`;
   }
@@ -1362,3 +1364,17 @@ function closeStatesEditor() {
   debug.selectAll(".highlight").remove();
   $body.innerHTML = "";
 }
+
+function updateLockStatus(stateId, classList) {
+  const s = pack.states[stateId];
+  s.lock = !s.lock;
+
+  if (s.lock) {
+    classList.remove("icon-lock-open");
+    classList.add("icon-lock");
+  }
+  else {
+    classList.remove("icon-lock");
+    classList.add("icon-lock-open");
+  }
+}
diff --git a/modules/ui/provinces-editor.js b/modules/ui/provinces-editor.js
index 3cac626f..692a4fa0 100644
--- a/modules/ui/provinces-editor.js
+++ b/modules/ui/provinces-editor.js
@@ -53,6 +53,7 @@ function editProvinces() {
     else if (cl.contains("culturePopulation")) changePopulation(p);
     else if (cl.contains("icon-pin")) toggleFog(p, cl);
     else if (cl.contains("icon-trash-empty")) removeProvince(p);
+    else if (cl.contains("icon-lock") || cl.contains("icon-lock-open")) updateLockStatus(p, cl);
   });
 
   body.addEventListener("change", function (ev) {
@@ -163,6 +164,7 @@ function editProvinces() {
           class="icon-flag-empty ${separable ? "" : "placeholder"} hide"
         ></span>
         <span data-tip="Toggle province focus" class="icon-pin ${focused ? "" : " inactive"} hide"></span>
+        <span data-tip="Lock the province" class="icon-lock${p.lock ? '' : '-open'} hide"></span>
         <span data-tip="Remove the province" class="icon-trash-empty hide"></span>
       </div>`;
     }
@@ -1086,3 +1088,17 @@ function editProvinces() {
     if (customization === 12) exitAddProvinceMode();
   }
 }
+
+function updateLockStatus(provinceId, classList) {
+  const p = pack.provinces[provinceId];
+  p.lock = !p.lock;
+
+  if (p.lock) {
+    classList.remove("icon-lock-open");
+    classList.add("icon-lock");
+  }
+  else {
+    classList.remove("icon-lock");
+    classList.add("icon-lock-open");
+  }
+}