diff --git a/graphile/graphile-connection-filter/src/index.ts b/graphile/graphile-connection-filter/src/index.ts
index 30c95ea35..44faf101f 100644
--- a/graphile/graphile-connection-filter/src/index.ts
+++ b/graphile/graphile-connection-filter/src/index.ts
@@ -49,6 +49,13 @@
  * ```
  */
 
+// Load the global type augmentations (inflection methods, build/scope
+// properties) so that downstream satellite plugins which `import
+// 'graphile-connection-filter'` pick up the `filterType`/`filterManyType`/
+// etc. type extensions without having to reach into the package's internal
+// file layout.
+import './augmentations';
+
 export { ConnectionFilterPreset } from './preset';
 
 // Re-export all plugins for granular use
diff --git a/graphile/graphile-postgis/__tests__/spatial-relations.test.ts b/graphile/graphile-postgis/__tests__/spatial-relations.test.ts
index 63165312b..d9fe6b1e8 100644
--- a/graphile/graphile-postgis/__tests__/spatial-relations.test.ts
+++ b/graphile/graphile-postgis/__tests__/spatial-relations.test.ts
@@ -67,8 +67,16 @@ function buildMockRegistry(
 }
 
 function makeBuild(registry: any): any {
+  // Minimal inflection double — only `camelCase` is consulted by
+  // `collectSpatialRelations` (to normalize the parametric arg name).
+  const inflection = {
+    camelCase(str: string): string {
+      return str.replace(/[-_](.)/g, (_, c: string) => c.toUpperCase());
+    },
+  };
   return {
     input: { pgRegistry: registry },
+    inflection,
   };
 }
 
@@ -289,6 +297,27 @@ describe('collectSpatialRelations', () => {
     expect(rel.paramFieldName).toBe('distance');
   });
 
+  it('camelCases snake_case parametric arg names', () => {
+    // The @spatialRelation tag grammar accepts any [A-Za-z_][A-Za-z0-9_]*
+    // identifier for the parametric arg; the GraphQL field we expose for
+    // it must follow the same camelCase convention as every other field.
+    const registry = buildMockRegistry({
+      clinics: {
+        pk: ['id'],
+        attributes: {
+          id: { base: 'int4' },
+          location: {
+            base: 'geometry',
+            spatialRelation:
+              'nearbyClinic clinics.location st_dwithin travel_distance',
+          },
+        },
+      },
+    });
+    const [rel] = collectSpatialRelations(makeBuild(registry));
+    expect(rel.paramFieldName).toBe('travelDistance');
+  });
+
   it('supports multiple tags on the same column (string[] form)', () => {
     const registry = buildMockRegistry({
       counties: {
diff --git a/graphile/graphile-postgis/src/plugins/spatial-relations.ts b/graphile/graphile-postgis/src/plugins/spatial-relations.ts
index daf4984ea..ba0f5f3aa 100644
--- a/graphile/graphile-postgis/src/plugins/spatial-relations.ts
+++ b/graphile/graphile-postgis/src/plugins/spatial-relations.ts
@@ -322,6 +322,13 @@ export function collectSpatialRelations(build: any): SpatialRelationInfo[] {
   const pgRegistry = build.input?.pgRegistry;
   if (!pgRegistry) return [];
 
+  // Inflection is used to normalize user-supplied identifiers (the
+  // parametric arg name, e.g. `travel_distance` → `travelDistance`) into the
+  // GraphQL casing conventions. Fall back to identity if not available
+  // (e.g. when invoked from unit tests with a stub build).
+  const camelCase: (s: string) => string =
+    build.inflection?.camelCase?.bind(build.inflection) ?? ((s: string) => s);
+
   const relations: SpatialRelationInfo[] = [];
 
   for (const resource of Object.values(pgRegistry.pgResources) as any[]) {
@@ -400,7 +407,7 @@ export function collectSpatialRelations(build: any): SpatialRelationInfo[] {
           targetResource: target.resource,
           targetAttributeName: target.attributeName,
           operator: OPERATOR_REGISTRY[parsed.operator],
-          paramFieldName: parsed.paramName,
+          paramFieldName: parsed.paramName ? camelCase(parsed.paramName) : null,
           isSelfRelation,
           ownerPkAttributes,
           targetPkAttributes,
@@ -431,7 +438,10 @@ export function collectSpatialRelations(build: any): SpatialRelationInfo[] {
 function spatialFilterTypeName(build: any, rel: SpatialRelationInfo): string {
   const { inflection } = build;
   const ownerTypeName = inflection.tableType(rel.ownerCodec);
-  const rel0 = rel.relationName.charAt(0).toUpperCase() + rel.relationName.slice(1);
+  // Normalize the user-supplied relation name (which may be snake_case,
+  // kebab-case, or mixed) into PascalCase so the type name is consistent
+  // with every other generated GraphQL type name.
+  const rel0 = inflection.upperCamelCase(rel.relationName);
   return `${ownerTypeName}Spatial${rel0}Filter`;
 }
 
@@ -638,7 +648,10 @@ export const PostgisSpatialRelationsPlugin: GraphileConfig.Plugin = {
             const FilterType = build.getTypeByName(filterTypeName);
             if (!FilterType) continue;
 
-            const fieldName = rel.relationName;
+            // Normalize the user-supplied relation name (which may be
+            // snake_case, kebab-case, or mixed) into camelCase so the GraphQL
+            // field name matches the casing of every other generated field.
+            const fieldName = inflection.camelCase(rel.relationName);
             // Avoid clobbering fields an upstream plugin may have registered
             // (e.g. an FK-derived relation with the same name).
             if (fields[fieldName]) {